If I am having trouble falling asleep it's usually because I'm stressed. My body is ready, but my mind isn't. Reading sometimes helps. I usually surf these forums because it keeps my brain occupied. A shower sometimes helps too, or a bath if you're feeling up to it ..
If I'm not trying to fall asleep but I'm reading, and I notice it takes me more than 5 minutes to finish a page, or I re-read a sentence a couple times and don't mean to, then it's "flip book closed and lights out" time... Sometimes this happens the second I open the book, sometimes up to 6 hours later. It's a good way to unwind.
I'd stick with natural stuff. You'll figure out how to shut your brain off. Personally I like to lay down and imagine I'm in my favorite movie or tv show, the main character, change up the story line. Ever since I've done this, I haven't had any nightmares.
As of 02/02/14: 5.5 Gallon NPT - Plat ----------------29 gallon - Awaiting bleach bombing and selling
46 gallon bow - 5 glass cats, 6 kuhlii loaches, 2 rasboras, 1 parkinsoni rainbow, 8 White Tip Tetras, 1 bristlenose pleco, 5 julii corydoras, 1 bolivian ram, 7 neon tetras , 2 female sunset gouramis, 10 dainty corydoras, shrimp and snails