I used to struggle with insomnia a lot, but for now I (knock on wood) have it under control. The trick is to have a routine. Simply having a routine is more important than the specifics, I think. Mine is:

- No caffeine after 3pm.

- Lower the lights as much as possible half an hour before bed.

- I have a playlist of Chopin nocturnes on my iPod I've been using for about 6 years now. I never listen to it except in bed. At this point my brain associates that music w/ sleep. Until I started doing this, I had a big problem with fast music getting stuck in my head and keeping me awake.

- Read in bed until I feel sleep coming on.

Again, routine is key. It especially helps when on the road, since your routine can help counteract the unfamiliarity of the surroundings.