How to make a study plan for your intermediate cl esp for bio, chemistry and physics?

I am a student of intermediate in pre-medical group. Whenever I pick my Bio,Chem or Physics book, I giveup while seeing the textbook having 400 pages each with lots of diagrams on one page and lots and lots of numerical problems to do. All, this all must be done in at least three months. oooooohhhhhhhhhhh..........??????????