I just try to blank out my mind if I have trouble sleeping, or let it wander freely.
I'm pretty sure I'd end up in a psych ward if I allowed my mind to wander freely :tinfoil:
I had trouble falling asleep for about as long as I've been alive. There are some things you can do though...
-Make sure it's dark - as dark as possible.
-Low level white noise - a fan works well.
-Earplugs - aside from the white noise, it's best to have as quiet of an environment as possible.
-Have a little air pass over your face... like from the fan... this also helps people with sleep apnea.
A boring TV show, and a timer are a great thing... set it up, and you'll fall asleep fast. Two things you should be careful about though... that the show doesn't turn out to be too interesting, and that the timer off function of the TV is not accompanied by some loud sound.
Likewise a text book is a great way to get sleepy.
Don't eat for at least 2 hours before sleeping. Don't drink for an hour before sleep.