For bio, flashcards worked well for me. I think I went through my stack of 500 cards about 6 times.
For O-chem, I'd work as many problems as possible. For me, that meant doing lots of homework problems out of the book.
For the PAT, I got an engineering text book from the university library. I found as many practice problems as possible, and I drew all of the possible views for each object. That helped me a lot with the keyholes, top-front-end, and pattern folding. For keyholes, I made up a bunch of my own practice problems. Finally, for angles and cube counting, I used Kaplan's materials to practice, practice, practice.