Lie down. Comfort is optional.
In my experience, becoming uncomfortable sometimes helps. It seems like something to kind of let go of, perhaps a way of disassociating me from my body. Anyways, lie still and do not move, especially when the urge to do so arises. My problem is thinking, endless thinking.
Just as with a meditation requiring a lack of thought, clear your mind and visualize the darkness around you, feel it. When thoughts arise, recognize them; don't try to force them down or crush them. Rather, guide your mind back to the absence of thought, to the darkness.
Breath, in and out. Don't try to count, don't make any effort to slow your breathing, simply breath. Then forget about your breathing. The body knows how to do this on its own. It may feel as if it's not working, as if you need to consciously inhale. Don't bother. Simply feel the darkness.
Being akin to black smoke, it swirls about gently, saturating your spirit, your personal energy. It relaxes you, fingertip by fingertip, eyelash by eyelash. When you feel completely relaxed, try to let the imagination of your mind take over, let yourself 'daydream' in this trance like sleep. I think of it as kick starting the dreams, so to speak.