If you get behind in the beginning, you are in big trouble. One way to warm up to a class is to check out what resources are available. A lot of college textbooks have companion web sites where you can find further explanations of the concepts in the book as well as self quizzes. The Academic Skills Center offers peer and professional tutoring and organizes study groups for a wide variety of classes. One often underused resource is your professor.
Professors have office hours for a reason.
They are there for you. Make sure you know where your professors' offices are, when they hold office hours, and what their e-mail addresses are. Be sure to keep all of your materials for each class together and routinely review your notes. There is nothing worse than beginning to study for an exam the night before and having to round up all of your notes from three or four different notebooks and put them in order. If you have to do this, you will be tired before you begin to study.