Yeah, the avoiding stimulants is big as well, at least for me. Strangely enough, I feel like that's one thing that's changed as I've gotten older - when I was younger, I could drink coffee right before bedtime and still fall asleep. Now, I find that if I don't cut out the caffeine well in advance of bedtime then it affects my ability to fall asleep.

I'm not very good at the "avoiding blue light" part, I really need to start doing that. But I'm really bad for surfing the 'net or reading some kind document on the computer, right up until time to close my eyes. :-(