If you're planning your class schedule before you actually arrive at college, be sure to leave some mornings free so that you can sleep late. You can only go so many days in a row on four or five hours' rest. Pack some earplugs. There will be nights when you're utterly exhausted and will need to conk out before dawn. Remember, sleep deprivation has been used as a form of torture, so don't suffer needlessly.
Cat naps can be quite refreshing.
Even 15 minutes' worth of sleep in between classes can keep you going. Don't abuse caffeine, in whatever form. You need to sleep to absorb what you are studying, so staying up all night before an exam will only have a negative impact. This is one roommate problem where there is the potential for help. If others in your dorm report having the same problem, then you can switch roommates so that you share quarters with someone who also likes to get to sleep at a reasonable hour.