How should I study for the following subject tests?

<p>Hello, I'm going to be a junior this fall and will be taking sat chemistry, sat physics, and sat math II in either June or May. I will be also be taking the classes: ap chemistry, ap physics 1, and ap calculus. How much do I have to prepare for these tests in order to get a high (almost perfect) score? Do the classes help a lot? What are the best prep books? Are used books no good? Help me out please :)</p>

<p>Bump</p>