Practice good time-management skills
Poor time management is the one thing that has taken down some the best students year after year. Taking control and managing your time can't be emphasized enough. Your entire schedule will be different from high school - you'll have much more free time but many more out-of-class academic responsibilities; you'll have no one getting you out of bed and to class in the morning; you'll have numerous new and exciting distractions tugging at you from all directions.
As Austin, a graduate of the University of Wisconsin at Madison said, "Just know that you are on your own, responsible for yourself. So do it right—immediately—so you don't have to fix a bad situation later. It's all about balancing your time between school and fun."