Carrots and raw eggs are thought to be especially beneficial, but all nuts are to be avoided. Overeating should be avoided. And no food should be eaten just before an OOBE attempt. In general, we see here the same kind of dietary restrictions advocated for kundalini yoga. Progressive muscular relaxation - This is one of the basic methods used in hypnosis and selfhypnosis.
Physical relaxation can assist one in attaining the requisite trance state.
These techniques involve beginning at the toes and tensing, then relaxing the muscles, progressively up the entire body. The practice of kundalini yoga is particularly relevant, since it is concerned with altered consciousness. If you can experience the feeling of being there, so much the better. And J.H. Brennan describes similar techniques where in the door is shaped and colored like a tattva, or alternately, a chosen tarrot card is visualized and the student visualizes entering into it. In many respects similar to visualization.