Do a lot of what sid said, where you re-read your notes to yourself to keep them fresh. Do practice problems, but also spend time explaining what happens in each step. Comprehension is more important than rote memorization. If you can explain it to a friend who is stupid on the subject and they understand it, then your making progress. Space it out. 1-2 hours a day will make a huge difference. Finally, Try to pace yourself with practice problems and review sessions that keep you on top of your game, and highlight your weaknesses. Before the exam study little, and spend most of the time explaining how things work, not practicing doing them. Dont study the night before, just digest what you have.