Schedule study time
With so many activities and fun things to do after class hours it can be easy to lose sight of what you came to college for.
Schedule time to study (preferably when you're not tired). Just like you have a class schedule, make a weekly study schedule and make an effort to stick to it. With a little bit of study each day and each week it will be a lot easier to ace those exams without having to cram or stay up all night to study for a test.