For a long time, my favorite television series was the original NCIS. The featured actor was Mark Harmon as Special Agent Leroy Jethro Gibbs. It was a repetitive riff that Gibbs had "rules," lots of them. They tallied up to 50 or 60 at least. New agents learned many of these rules from Gibbs himself or from longer tenure agents.
Rule #6 was, "Never say you're sorry." In the context of the show, the rule made sense. Gibbs was a veteran US Marine. Marines take responsibility for their error and act to correct them if they can. They strive never to make the same error again. "Sorry" is an unnecessary expression of weakness. "Sorry" has no utility to a marine, except, for example, when expressed to console a victim. Then "sorry" has utility.
In one episode, one of the characters asked Gibbs how many rules he had? Gibbs answered that he didn't know because he hadn't written them all down yet. Implied was that, as new situations arose, one might add new rules or revise or discard some. It's the same for your meditative practice. Only, we'll call our rules "principles.”
Let's examine a few.
Acceptance: Have you ever considered or participated in "improvisational" theatre or improv comedy? Improv is an exercise in spontaneous action. Two or more people are on stage. A coach or moderator tosses up a subject or a situation. Unscripted, the participants improvise dialog and action. Each exercise ends in one of two ways. Participants exhaust the possibilities of the scene. Or, one of the participants blocks the other, and the action stops. Blocked in improv is the opposite of Acceptance. Successful improvisation requires one to accept in word and act. Living is continuous improvisation.
In sports, Acceptance is the willingness to receive the ball and press to the goal. Simultaneously, it's a willingness to pass it to another player with a more straightforward path to a score. In short, be a team player.
[Personal disclosure] I tried improv comedy once. I was not much good at it. I was o.k. accepting the theatrical ball, but not so adroit passing it on. I'm more intellectual than emotional. I tend more to resolution than to process. I was not open to flow. Even though I was inept at the exercise, it was a helpful lesson in communication. Indeed, it has enriched my interactions with others since. Give it a try sometime.
Resolve to accept what I offer in this text on its face. Nothing you learn here will damage you. Nothing you do here is unchangeable. Discernment and choosing will come later, with practice and experience.
If you are pursuing meditation as a part of a group or classroom instruction, be open to others' contributions. Accept that you and everyone are worth hearing. Flowing interaction between participants is of inestimable value. Offering polite counter-opinion or a different experience is acceptable. Pose it in a way that furthers the flow.
Most important—ACCEPT YOURSELF! Spiritual practice is a deep dive into yourself—it's not all unicorns and fairy dust in there! Each of us consists of light and dark, expertise and ineptness, good and not so good. We're all saints and complete boneheads now and again. I do not exclude myself from that observation.
Meditation is spiritual alchemy.  What is alchemy? Alchemy is a medieval forerunner of modern chemistry. The science focused on creating a "philosopher's stone" (Latin: lapis philosophorum). It was also described as the Elixir of Life. Alchemists believed the elixir could transform unlike substances, such as lead, into gold. Organic matter, mind, philosophies, religion, magic, and astrology were all expressions of God. They believed the Elixir of Life was God's unifying substance.
Once acquired, the elixir could cure any disease. It could stop or reverse aging. Philosopher's stone was the key to rejuvenation, vibrance, immortality, enlightenment, and heavenly bliss. It was connected to the anima mundi, the "soul of the world." Crazy stuff, eh?
Today, quantum physics suggests that everything in creation consists of the same stuff, which presents an infinite difference and endless variety. In 1980, American Nobel prize-winning scientist Glenn Seaborg succeeded in transforming a very tiny amount of bismuth—a brittle metal that shares characteristics with lead or tin—into gold, with a nuclear reactor. 
Spiritual alchemy posits that all the energies innate in you are the same stuff, along a polarity axis. You cannot have just one pole—the positive one. You cannot have light without dark. Suppress your negatives, and they will flare up ever larger. Excise the negative—think of the horrid medical practices of frontal lobotomy surgery or electro-shock therapy—the good stuff and all nuance in-between disappears, as well.
Spiritually, the alchemical process of transformation and synthesis is meditation. Compassion, forgiveness, or love can be produced from anger. Mis-focused sexual energy transforms to bravery, determination, focused action, and as well, love. Accept and feel grateful for your natural resources regardless of polarity. They are all the same transformable stuff.
A Japanese Zen teacher says:" Sin and enlightenment are two sides of one coin. When you think you are sinful, you have enlightenment. And the enlightened mind says you are sinful."  Developing a deep understanding of this is part of spiritual awakening.
Another teacher asserts, "Acceptance is transcendence. And if you accept yourself totally, suddenly you are thrown to your center. Then you cannot move anywhere. You cannot move from your suchness, from your nature, so you are thrown to your center."  I recall many times sitting with American Catholics practicing "Centering Prayer."
Simplicity: Picture this: My own Zen Buddhist tradition practices intensive silent sitting retreats a few times a year. While practitioners regularly sit an hour or so a day, intensives [Jap. sesshin] requires meditating anywhere from 6 to 9 hours per day, stretched over as many as seven days. Even meals are taken formally, without relaxation, at one's sitting place in the meditation hall.
Hours upon hours, sitting stock still in a dark hall, in older times smoky with incense, legs folded like a pretzel, tingling if they haven't lost feeling altogether. The back hurts. Nose itches. How many minutes remain in the sitting period? It doesn't matter. Each will be a mini-eternity of combat with oneself. It's an emulation of sorts of Bodhidharma, historically the first Chinese Zen patriarch, legendary for sitting grim, emaciated, sunk-eyed, for nine years, his gaze fixed on the wall of a cave, in a relentless meditative slog to enlightenment. 
Pretty much everything described stems from the Buddhist, later samurai influenced, traditions of Zen. Little is intrinsic or essential to the core meditative practice— silent sitting.
Some Zen centers do not allow meditators to attend long intensives without considerable experience and special screening by practice leaders. Indeed, participation may yield profound experiences or quite the opposite, due to the physical and psychological intensity. My teacher cautioned against placing too much emphasis on mystical experience, enlightenment. The historical Buddha is said to have tried and rejected practices of severe austerity, deprivation, and mortification.
Meditative practice does not have to be arduous. It's not a quest for a holy grail. A theme in much of grail literature is that the hero spends considerable time, effort, torment, and proverbial shoe leather seeking to find what he possessed all the time. What we seek, we already have. So why do we meditate?
Because "THAT" is buried, covered over, way down at the bottom of our toy box. What this means; spirituality is innate in you. It's just covered up or covered over with other stuff. It requires some effort to locate it, reveal it, and dust it off. Relax. You are already spiritual. There is nothing to add to you, nothing to discard. You are complete. From the inside, it's sometimes difficult to see. A little (or a lot) of housekeeping is needed.
Permit me a short detour. While I did not grow up in the Christian faith, I count myself fortunate to have grown up in the golden age of Christian television evangelism. From the black and white days of Rex Humbard, Oral Roberts, and Billy Graham, into the age of color with Jimmy Swaggart, Jerry Falwell, Jim, and Tammy Faye Bakker. Even in our contemporary flatscreen age, it continues to be a favorite spectator sport of mine to dial in Joel Osteen, Joyce Meyer, or the delightfully monikered Creflo Dollar and others. Why? Genuine or scalawag, televangelists are master communicators: complex, intricate maestri, lithe dancers, and incredible illusionists.
Recently, I dialed in a Christian evangelist whose forte was biblical exegesis—interpretation of scripture through detailed textual analysis. In the space of a few minutes, she filled three giant whiteboards with a vast quantity of scribblings in an array of colors. Arrows, like long-tailed comets, darted here to there. Wide circles corralled this and that; all of it accompanied by a blisteringly fast narrative. This word means this in Aramaic and that in Greek and this in English from the King James translation, the New Revised English translation is quite different--yada yada.
Much of her performance flew high and fast over my head, and I know something about her subject. She gyrated an esoteric song and dance. She was exciting, breathtaking, authoritative, and hypnotic. Ultimately, [forgive me!], the whole schtick was intellectually masturbatory to anyone, not an exegetical scholar. I don't wish to mock my evangelist. She defines terminology as a career. For the rest of us, even a modest complexity can trap us on an endless rat wheel that gets us nowhere.
You will not find much complexity in this text. What complexity there is will be in footnotes or comments. At CloudMeditation, we prefer English to foreign words wherever possible. The material that underlies all said here is breathtakingly, beautifully simple. Nothing you will learn and do here requires abundant intelligence to understand or any esoteric skills to practice. Don't underestimate the power contained within the simplicity.
Do, rather than think!
Utility: At CloudMeditation, we strive for everything presented to be useful and usable to you. We want you to fill a spiritual toolbox—not just with one tool—likely, you will find several that work for you. You will construct a meditative practice tailored to you. You will take control of your spiritual practice as swiftly and as capably as possible. Try it all. Use what you can use now. Set aside the rest. You can always come back to it.
How do you know what is useful—when a technique is working? For most, the perceptions are subtle, for some, stronger. A method's effectiveness manifests in different flavors, thoughts, feelings, and sensations, unique to the person.
If the technique fits you, you may begin to feel a different YOU in you, like Alice in Wonderland not feeling herself. You perceive a subtly different identity that coexists more or less equally or at a deeper level within you. Through this identity, you are capable of observing your usual self.
"The eyes are the same, but the looker behind them is different."  The subtle separation of identities indicates a tool—a technique—you may wish to work with more extensively. If you remain the same and do not feel any difference, nothing is happening. Set it aside.
Positively, you may feel inner tension, conflict, tautness within you relax a little or a lot. Again, this can be subtle, graduated, or immediate and cathartic. I recall parts of a brief poem or haiku that described "falling into one's own arms" and the speaker within the poem asking, "what kept you so long?" 
Unburdening is another description. "You will begin to feel, if the technique fits you, that gravity has become reversed. Now the earth is not pulling you down. Rather, the sky is pulling you up." 
Imagine the notion of "walking on air." Recall a time when you might have felt light, almost weightless. Lovers express such sensations often.
Or, when your bat connected with the ball in an unimpeded, completely thoughtless motion, effortlessly, and sent the orb soaring over the fence. Likely, you felt feather-light on your feet around the bases.
You may feel inner levitation, an emotional lightness. Open your eyes. You're grounded. Close them. You're floating a bit. The technique may fit you.
If a technique fits you, "normal" will be—again subtly, or maybe more so—different. You walk differently, sit differently, eat differently. Everything will be subtly different.
Here, it is important to recall our principle of accepting our full range—the complete arc of our energies between the polarities. A human can cry in happiness and laugh in despair. A useful technique's positive manifestations can also elicit fear, anxiety, anger, sadness, longing, grief, tears, emotional welling up, and any increment of natural energy along the arc. Why is simple.
We don't like to unmoor from our "normal." We don't like not feeling ourselves. Our self is like an old favorite coat, moth-eaten, stained, torn, and tattered here and there, but it fits. It's comfortable. A new one feels too different.
The tension between the old, the routine, the boring, and this new "normal" may feel like a disassembly, a loosening of bolts, a "not like yourself" perception of unfitness. Understand, nothing outside you has changed. Only you have become different. Shortly, you'll come back into alignment at a more attuned level.
So, be patient, worry not. Don't accord any of these—either positive or negative manifestations—too much importance. Just observe. Be neutral. It will pass, as it should.
Neutrality: That subtly different coexistent identity within you is innately a neutral observer. When polarized energies settle, they settle to relative neutrality. Let's investigate other aspects of the principle of neutrality.
Meditative practice is A-MORAL—i.e., neither moral nor immoral. Morality is irrelevant because meditation is a science—like medicine is a science. If you administer the proper medication in the correct dosage, over the right course of treatment, to an ill thief, it will likely cure the thief. If you do the same for a sick saint, the saint will probably recover as well. Morality is irrelevant to the efficacy of the right medicine, as it is to meditation.
DON'T MISUNDERSTAND! Immorality is not o.k. An immoral person has a disturbed mind. As good as most of us are, we misbehave on occasion. It results from a troubled mind. Meditation calms and corrects mind disturbance. It's irrational—as a precondition— to require that one must be or become moral to take up a meditative practice.
Meditative practice is A-RELIGIOUS—i.e., religious belief or non-belief is irrelevant. Techniques you learn at CloudMeditation are a sampling of 112 contained in a Vedic text called the Vigyan Bhairav(a) Tantra.  All three words have different meanings in various languages (ex. Pali or Sanskrit) and what they express in other religions (ex. Hinduism, Jainism, or Buddhism).
Vigyan is sometimes translated as consciousness, understanding, perfect knowledge (of). In the context of my Zen Buddhist tradition, I might add the synonyms aware (of) or awake (to).
The text derives from a strand of Hinduism known as Shaivism, for which Shiva represents the supreme deity. Bhairava is one of a myriad of Shiva's manifestations. Bhairava has also been translated as a "tremendous or terrifying one," in the same sense that a deep or dramatic "mystical or spiritual" experience has been called a Mysterium Tremendum.  At once, the experience is a "daunting awfulness and majesty" and "something uniquely attractive and fascinating"—divine wrath and judgment, or divine grace and love. There are those polarities again. For us, Bhairava may translate the Supreme Being, Essence of the Universe, Creation, God--or my favorite, "the Unborn, the Undying, the Uncreated, the Undestroyed." 
Tantra translates as ritual, practice, method, in the sense of a how-to manual.
Vigyan Bhairav(a) Tantra is a how-to manual to perfect knowledge, to god-consciousness. We'll call it the VBT, for short.
I'll bet you're thinking, wait a sec, you said religious belief or non-belief is irrelevant to meditative practice. This VBT sounds religious! You're right and right again. As a practical matter, religions afford us vocabularies to express the inexpressible, the ineffable spiritual—sometimes called mystical—experience. We use religious sources to illustrate and instruct more often than non-religious sources, simply because there are so many more of the former. A mature spiritual tradition has a well-developed vocabulary to aid us in our understanding. The VBT is part of one of the oldest extant and most well-developed expressions.
Transcribed more than 2,000 years ago, it may derive from older written text and even more ancient oral sources. It's a safe bet that the 112 meditative practices outlined in the VBT predate most, if not all, contemporary religions. Indeed, one can associate a fair number of the methods outlined in the VBT with practices in many of our current religions: Catholic, Protestant, Quaker, Buddhist, Islam, Jewish. And you will also recognize methods associated with some aboriginal cultures from around the world.
Recall that meditative practice is a-religious. It's neutral. A reflective practice accepts that beneath all human facades—beneath the mask of persona, is a spiritual essence common to us. Innate within the Christian, Hindu, Jew, Buddhist, Mohammedan, agnostic, and atheist are the same energies as you or I have.
Fun!: Ah, the best principle of all! Have fun. Meditation is not Bootcamp! Strap in for a thrilling ride. Wear a helmet and a cup! Dive in the deep end! Hang off the cliff! Schuss the Black Diamond! Float like a butterfly! Tuck your chin down and take it up the middle! All right, I think I've exhausted all my sports metaphors for now.
Take heed of comfort—no thrill, no bumps, no bobbing, and weaving—the practice or technique may not be for you.
Take heed of discomfort—gettin' smacked around a bit, slightly off your game, gotta work at it—that just might the practice or technique to add to your spiritual toolbox.
The key to both is affinity--a natural liking for or similarity of characteristics suggesting a relationship. Affinity applies both to techniques that fit and ones that don't. The qualities of that affinity are different. Association that offers comfort with the status quo—remember that old ratty coat—probably not a good fit. Association that stimulates, sharpens, puts one slightly off-balance—probably a good fit. Keep a spirit of play!
Let's play with just one technique today.
VBT Technique #43:
"With mouth slightly open,
Keep mind in the middle of the tongue.
Or, as breath comes silently in,
Feel the sound ‘HH’."
I practice this technique quite often, in bed or while working, sitting, standing, active, or not.
Curl your tongue into a "U" shape as gently as you can. Breathe in through your mouth with a very slight audible "sss" sound (the sound is optional). Feel the breath cross your tongue. As you breathe out, close your mouth and exhale through your nose.
I find the technique produces very long deep abdominal breaths, which are healthy, calming, and focusing. For very active minds, the method slows one's breathing considerably. It allows more accurate consistent breath counting as a focusing exercise (1 to 10, 10 to 1, in-breaths, out-breaths, in and out breaths; whatever you prefer). Eventually, the technique, the counting; all of it dissolves to just being.
 Osho. The Book of Secrets. Osho International. Kindle Edition.
 "Objects and Stories:" http://sciencemuseum.org.uk – Base metal for sure, in one of its forms, bismuth subsalicylate, has been used to treat diarrhea. (In addition to plutonium, Seaborg is credited as a lead discoverer of americium, curium, and berkelium, and as a co-discoverer of californium, einsteinium, fermium, mendelevium, nobelium, and seaborgium. He shared the Nobel Prize in Chemistry in 1951 with Edwin McMillan for "their discoveries in the chemistry of the first transuranium elements.").
 Zen Master Shunryu Suzuki [San Francisco Zen Center] July 29, 1965.
 Osho. The Book of Secrets. Osho International. Kindle Edition.
 Bodhidharma lived during the fifth or sixth century. He is traditionally credited as the transmitter of Zen [Chinese: Chan] Buddhism to China and regarded as its first Chinese patriarch.
 Osho. The Book of Secrets. Osho International. Kindle Edition.
 Though I've researched diligently, I have not succeeded in finding this brief verse again; therefore, I cannot attribute it. If anyone can, please email me the citation.
 Osho. The Book of Secrets. Osho International. Kindle Edition.
 There are several translations of the VBT, each with its strengths and weaknesses for the western reader. We rely on three:
Chaudhri, Ranjit. Vigyan Bharaiva Tantra: 112 Meditations For Self Realization. New Delhi: Prakash Books, 2008.
Singh, Jaideva. Vijnanabhairava or Divine Consciousness: A Treasury of 112 types of Yoga. Delhi: Motilal Banarsidass, 1979.
Sharma, Dr. Narinder. Vijnana Bhairava Tantra: Sanskrit text with English translation. https://archive.org/details/VijnanaBhairavaTantraSanskritTextEnglishTranslation_201804/page/n7/mode/2up
 “[W]e are dealing with something for which there is only one appropriate expression, mysterium tremendum . . . The feeling of it may at times come sweeping like a gentle tide pervading the mind with a tranquil mood of deepest worship. It may pass over into a more set and lasting attitude of the soul, continuing, as it were, thrillingly vibrant and resonant, until at last it dies away and the soul resumes its “profane,” non-religious mood of everyday experience. . . . It has its crude, barbaric antecedents and early manifestations, and again it may be developed into something beautiful and pure and glorious. It may become the hushed, trembling, and speechless humility of the creature in the presence of—whom or what? In the presence of that which is a Mystery inexpressible and above all creatures.”
Taken from Brittanica.com, the quote is from the book The Idea of the Holy, a classic religious studies text by Rudolf Otto (1869-1937), first published in German as Das Heilige - Über das Irrationale in der Idee des Göttlichen und sein Verhältnis zum Rationalen in Breslau in 1917.
 Zen Master Jiyu Kennett.