Use a student planner, don't just own one. Keep track of what you need to do and when you need to do it. Never get surprised by a test or assignment due date.
Attend your classes, it takes less time than trying to learn everything on your own. After each class organize your notes into a three-ring binder dedicated to that course.
Sort your stuff. Organize and save computer work. Keep all tests and assignments that are handed back to you. Date your notes to keep them order. When it comes time to study you won't waste time finding what you need.
Use the time you have, not the time you wish you had. You can't say yes to everything and still succeed. Make time for the necessities such as school, work, family, exercise, meals and sleep then priorities your other activities.
Schedule study time. Fix 2 to 3 hours of time outside of class for every hour you spend in class. Use this time to do assigned readings, make notes, work on assignments and when you finish all of that, review!
Priorities. Make a To Do List starting with everything you need to do. Then rank them according to importance.
Reward yourself. Make sure to schedule in clubs and activities you enjoy. Without the fun you'll be too stressed out to accomplish anything. Just remember that if Thursday is going to be movie night then work needs to get done at other times.