For review purposes, I would highly recommend Chad's videos. His website is full of instructional videos that are easy to get through and very helpful with broad overview of material. You could spend all summer studying half your physics textbook, but the OAT is designed to test you on a very wide variety of subjects. You're main goal is to bring what you've already learned to the surface of your mind and be able to apply those principles in basic ways. Use other sources for practice exams. If I had to go through the process again, I would have taken many more practice exams.