[Skipbidder]

Don't read in bed.
Don't do anything in bed besides sleep and sex, actually.
Watch the caffeine intake.
Don't eat close to bedtime either.
Have you made your bedroom as noise-free as possible?
Are there pets in your house? These are a common cause. Pesonally, I can't bring myself to lock my cats out of the room, so I live with the [censored] sleep.

If you wake up and can't get back to sleep quickly, get up. Do some exercise. Seriously. If you aren't going to do some exercise, go play one set of SNGs. Do something that requires some thought for half an hour to an hour, then see if you can get back to sleep. This will only be good if you can manage NOT to stew about things afterwards. I can't, so the exercise is the better option for me.
Don't nap during the day.
Try to get into a routine for when you get up and when you go to bed. Falling asleep itself isn't your problem. If it were, then I'd advise you to try to get to sleep, then if you can't after about 20 minutes, then get up and do something (like exercise) for 30 minutes, and try again.
A routine may be tough for you maintain as a student. You've got late night cramming and carousing to do.

You are unlikely to actually need a sleeping pill. If you do get one, it's likely to be Ambien. My personally prescribing preference is currently for off-label low-dose trazodone.