I have a hell of a time getting to sleep for one reason or another. Lengthy details and explanations aside stuff that has helped me tends to be making sure I am warm enough and that I'm not going to bed hungry. I often find I sleep quite well after having a snack, or I'm more likely to fall asleep.
Apparently white noise supposed to help, especially with babies, and I've found that in the few days since we've plugged in an air-filter with a quiet but still noticible motor, I've slept a lot better. Of course, it could also be the cleaner air. I know I like quiet when I sleep but I'm just as likely to stay away when it's dead quiet as when it's loud.