I've found that doing something relaxing before going to bed helps me prepare for sleep i.e. watching a good film or listening to music. Coming on the computer right before bed I find can make it harder for me to go to sleep.

I've also read that avoiding high protein foods before sleep can help you drift off as they stimulate the mind more than carbs in the long-term - protein being brain food. So, a bowl of cornflakes or something before bed might help you sleep better than something high protein like cheese or meat (for those who eat them).