Learn how to be *consistently* successful academically.
If you go into college not really knowing how you, personally, are successful in school (ie, what it takes to force yourself to do homework, or what study methods work well for you for tests, or what kind of strengths and weaknesses you have in learning styles), you'll just flounder (like me!). It took me a long time to figure out that I can't do homework in certain places (on the couch), that I can't study in front of the TV because I can't split my attention between the show dialogue and retaining what I'm reading, that I'm a visual learner and 100% not auditory, and the methods of studying that work for me (flash cards no, quizzes yes.) After that, you only need to worry about whether you have the self-discipline to follow through with this kinda stuff.