When studying for any exam or test, its important to start with the text-book and notes taken inside or out of class. The most effective way i found of studying was using flash cards on quiz let and watching crash course videos on mrbrock.net. Mr.Brock uploads his own flash cards and videos which can help you a lot if you study his set plus your own. When preparing for the mid-term and final, go through all your flashcards and pick out the ones you didn't really know, also by using quiz let make vocabulary terms and study them. The more terms you know, the more you will understand about what has happened and what's going on.