Studying for AP Exams?

I will be taking AP US History, Biology, English Language, and Latin in May. I don't think I really need to/can study for English, and I think Latin is a lost cause altogether (any advice on that one by the way?). I have the Barron's AP Biology review book and the REA Are you Serious about Getting a 5 AP US review book. I don't really remember much in from what we've learned this year, so I would like to go over everything. With not much time remaining, how can I relearn US and Bio? How long should I spend each day with these books and how should I break down the studying? Thank you for all advice!