The most important thing is not to worry about it, which is sometimes easier said than done.

Just relax and know that when your body really needs sleep you will not be able to stay awake.

Whatever you do don't try to write a song or do anything equally important.

Most people sleep more than they actually think they do. I usually wake up two or three times during the night and just turn over and go back to sleep or just lie there and relax and I don't let it bother me.

Or read Chaucer's "The Knight's Tale", I bet you don't finish it before you're asleep.