If you watch the activity of your mind as you drift off to sleep, you might notice going into a state where you experience vivid imagery and the mind wanders wildly from one thing to another. This is the hypnogogic state. I have a page on my web site that discusses how to recognize this state, how to enter it using relaxation exercises, and how to use it to experience psychic phenomena.
If you learn to recognize the hypnogogic state and practice being in it, you many find that it leads to another deeper state. I call this deeper state the "beyond-the-hypnogogic" state. The vivid imagery stops and one feels more alert but it is not normal consciousness. The body is deeply relaxed as in sleep and the mind does not wander wildly. One may feel like he is floating and/or in a vast expanse of space with little or no sense of having a body. Any emotional turbulence or upset that might have existed previously is absent, and this tends to carry forward even after you return to normal consciousness. It is also easy to enter the joyful meditative state from the beyond-the-hypnogogic state.
There is a simple method you can use while in the hypnogogic state to help bring on this deeper state. First enter the hypnogogic state. An easy way to do this is to meditate as you are lying in bed when you go to sleep for the night. Meditate by noticing your breathing. Say to yourself, "in" as you inhale and "out" as you exhale. Most likely you will become drowsy in a few minutes and experience vivid mental imagery and your mind will wander wildly. This is the hypnogogic state. Each time you become distracted from observing your breathing, when you experience mental imagery or your mind wanders, try to describe as best you can in a few words what you experienced. For example, if you experienced imagery of a grocery store you could describe it as "seeing a grocery store", or just "grocery store". Sometimes you might not be able to remember what you experienced. In that case just describe it as "imagery" or "distraction". Then continue meditating. The mental activity in the hypnogogic state arises from the unconscious. By describing that mental activity as best you can, you practice bringing the conscious awareness into the level of the unconscious. As you do this, it becomes easier to move consciousness beyond the hypnogogic state. This practice is similar to the practice of "noting" in Buddhist insight meditation and to the practice of "witnessing" in Himalayan yoga.
If you have trouble entering the hypnogogic state, the article Why is it so hard to concentrate? Sources of distraction and obstacles to concentration during meditation. might help you identify and deal with the problem.
The beyond-the-hypnogogic state is similar to other states you may have read about. Robert Monroe wrote about a state he called "mind awake, body asleep" that is favorable to inducing out-of-body experiences. In the Buddhist tradition, there is a state called "boundless space" or The Base of Infinite Space. In Himalayan Yoga, there is a recognized state between dreaming and sleep called Aladani, that also seems similar to this state. If you are interested in out-of-body experiences, Buddhist meditation, or Himalayan Yoga, you might find that practicing being in the hypnogogic state is a short cut to attaining these states. Since the hypnogogic state is something most people enter naturally as they fall asleep, it is relatively easy to learn to enter. The page on my web site that discusses this state explains how to recognize it and how to learn to enter it by doing relaxation exercises.