"All human evil comes from a single cause, man's inability to sit still in a room!"
— Blaise Pascal
The ancients believed stillness to be a relative state of motion attained gradually, since all things are in constant motion, only different degrees of motion, even when they seem otherwise. They so believed, long before the advancement in science when we could see the actual movement of electrons, photons, beams, etc. However experienced with stillness one is, one cannot stop all body organs from moving or functioning, except by death. We can only achieve some stillness, while we are alive, to re-energize life, by that free constant on-demand re-birth.
Like body-stillness, complete mind-stillness is a virtual state too, even during sleep and vegetative states. The brain stops only by clinical death.
Long sessions of complete body-and-mind stillness are needed from time to time to renew one's energy. Shorter sessions, or intervals, are also needed, but they are not as fruitful as the long ones. The calmness stillness induces has a long list of benefits.
Keeping our mind moving (thinking) while our body is still, gives us the freedom to further explore our mind and re-consider things in a way that our fast-moving life wouldn't allow us to. So we give ourselves that opportunity to stop and think, rather than wait for life to STOP us. Such stops give us a sense of direction, more self-control, and a sense of well-being without which life loses its meaning: we keep moving like robots, taking orders, and playing the roles assigned to us for the rest of our life, until we are forced to stop, permanently.
1. Still sessions should be prepared for by minimizing all causes of physical stress inside us and disturbance outside us. However, if there is some that cannot be helped, it won't be felt eventually because of the soothing chemicals stillness induces, that can overpower stress, screen disturbance, and minimize pain. When moving is a must, it should be minimal.
Stillness is preferably preceded by relaxation. It's more challenging to stay still when one suffers pain or stress, physically or mentally. Stillness, which is the same as "maximum slowness," better inhabits a care-free, relaxed body with no/minimal resistance, than a tense one. It's easier to live in peace when there is no enemy to fight: stress, ache, trouble, etc. Loosening up makes stillness more natural and rewarding.
2. We are like vehicles that cannot be stopped suddenly, without some inevitable damage. If beginners can't reach stillness immediately, they can slow down gradually. When they master it eventually, they can get into stillness quickly or instantly.
3. However enjoyable relaxation is, it is only a tool to achieve deeper longer happiness (and so are other fun-movements: walking, swimming, dancing, etc.). Thus, one needn't take so long relaxing to reach stillness, because relaxation itself is a type of movement that we want to minimize too. We must get into the still mode directly when we can, as stillness itself can handle the tension. When stress is inescapable, ignoring it is the best weapon to fight it with.
4. After we reach stillness, it's better to keep it long and complete to have optimal benefits. It's a basic fact to learn that "it takes longer time for our body to be calm, than it takes to be tense!" (Just like water that can be instantly disturbed, yet taking several minutes or hours to be calm again.)
5. Since calmness leads to stillness and stillness leads to calmness, we can use some tools of calmness to achieve stillness too, such as avoiding physical and social disturbance caused by over-talking, overeating; overwork, restlessness; stressful jobs, people and environments; harmful urges and bad habits; hypomanic obsession with arts, sports, travel, sex, and people; etc. On the other hand, one should seek silence, solitude, rest, peaceful environments, positive habits and conscious pleasures.
6. One should always include a pleasure part in every action they take in life, that would otherwise be meaningless if it's not lived for pleasure. Just as narcotics are prescribed for spasms, chronic pain, depression, etc., so can we use our own body-made narcotics to do the same job. There's nothing like pleasure to give satisfaction, as the relaxing endorphins induce the need for rest and motionlessness, while enjoying life at ease, in silence and tranquility. (Only a happy man can say, "Now, I can in die in peace."; and so he who wants to rest, sleep, or stay still. For what's the meaning of dying, sleeping or resting, after a long miserable day/life?)
7. Silence is to have a still tongue (and other speech organs too): it helps achieve stillness of body and clarity of thought. Talking leads to talking, and the faster, louder, longer, and higher (pitched) our talk is, the more likely we lose control over what we say, making mistakes and slowing down higher brain functions, just because of that most abused organ in the body—the tongue—we unnecessarily occupy with the primitive act of noise-making, like other animals do. (We humans have better, civilized means of communication.)
8. Having still eyes, ones that are not roving, helps concentration, rest and sleep. It's better to close/slow/fix our eyes (on something), as long as we have no urgent need for them, to avoid unnecessary "visual disturbance." However, once we focus our thoughts, the brain will work faster and the movement of eyes becomes less disturbing, as the inner ones (of the mind) will be busy, having all our attention, whatever is happening in the external world before the physical ones.
9. Other known techniques helping achieve stillness are
Stillness and motion complete each other. However, stillness is superior as it allows more neural movement of the "mind," which is superior to the body. Also physical "breaks" are healthy for the body itself. Stillness, or at least slowness, is vital for wisdom, yet life is impossible without "some" motion.
When stillness is not needed, there are ways to easily quit stillness and avoid its harms, gradually, not suddenly, to avoid health risks:
As humanity evolves, more work will depend on the brain and machine, and less on the body; physical movement will be minimal, while slowness/stillness becomes the norm and motion only limited to basic survival needs. Stillness will be maximal, all day, all life long, as we think more and move less, keeping the mind active and the body still, like an atrophied organ. In The Last Question, Isaac Asimov suggested that we will totally do without our bodies, that we may still keep anyway, somewhere, safe and sound, but unused, while our minds will be freely traveling, at maximum speed. However, for the nearer future, the picture will be close to this: