I've used this method to relax myself into falling asleep. I have other issues with finally getting asleep, but this method can make one really comfortable while in bed, with being uncomfortable my prime enemy to sleeping.

Start at your feet. Believe it or not, you have nerves which go through all the way down to your feet. () Imagine that you have a sort of muscle in your foot that you can flex from within. Another way is to imagine a single throb sensation in your feet. At the moment which you make your feet "react", exhale from a deep breath. If done correctly, then your feet should feel like they are sinking into your bed, when they really aren't.

Proceed with the imaginary reactions from your feet, to knees, thighs, hips, chest, shoulders, arms, elbows, wrists, fingers, and finally, your head. If this simple technique works for your body, then in the end you should feel like you have sank a few inches into your bed, and you'll be very relaxed.

Someone try this and tell me if it works for anyone else other than me!