Too Early to Study???

<p>Hi,
I am planning on taking three subject tests in May (Math II, Literature, US History) and World History in June. Obviously, I am planning on studying for all four quite a bit. My question: is it too early to start studying? I have not learned all of the material for the history tests (no AP, but IB HOA). Plus, I really need to score 700+ for all, since there are few opportunities to retake as a senior. Does it make sense to work through the Barron's books starting now, then move onto practice tests? I see many people here pick up the books maybe a month before the test. Besides, how does one even study for history? Flashcards?
Thanks for the help</p>

<p>This probably isn’t that helpful, but I took the Math II in June of 2012, I found the Barron’s extremely helpful. It was very difficult and I never scored above a 730, but I breezed through the actual exam and had plenty of time to check my answers. I got an 800 :D</p>

<p>I’ll be taking US History this May or June, I’m just using my AP stuff (REA, Princeton Review, Barron’s flashcards, and notes/outlines from the class)!</p>