Try Hemi-sync to aid in astral projection.
Or listen to some very soothing meditative music at very low volume and concentrate on breathing and relaxing. Relaxation is the most important aspect in astral projection.
Here is a yahoo group:
William Buhlman is an excellent author:
Here is a site that sells hemi-sync CDs.
I have had the most sucessful projections after about 4.5 hours of sleep, which is three 90 min sleep cycles. It seems to work best then.
Try not to move too much or at all when you wake up.
If you can set an alarm that stops after a minute or so by itself and remain motionless, you will have much greater success. Your whole body will remain relaxed. You should lay on your back. The room should be pitch black if possible. Also, try to be alone in the room. This helps, but is not completely necessary.