Well when i had a lot on my mind or had to remember thigs i needed to do the next day, i couldn't sleep. i was constantly thinking about those things i needed to remember. After a few days i was searching on the web and found some tut about how to stop thinking and clear your mind. It could be a placebo effect, but it worked for me
Do you have the source?
Best I can come up with is take a warm bath 30 minutes before bed with some bubble effect or something + your girlfriend, music or whatever.