Hi arri,
I used Crack the PCAT by Princeton Review , it's a good source to improve on the biology, chemistry and math section, though it goes into a much detail especially the biology topics (excluding plants). So what I did was skim through each chapter and basically underline or highlight anything that was new to me, again not everything I would underline. For chemistry, I took many chemistry courses so I have a solid background in the topics, I only did Dr.Collins and anything I get wrong I would write the concept of that question on a separate piece of paper and put it in a folder named (REVIEW BEFORE EXAM). i did that for all three sciences.
For Math, I started with 60-70 on my Pt#2 and went up bit by bit. What I did is used Princeton review for all topics but the problem i faced was there weren't enough examples given by the book. So what I did was read about the topic, go on Google and find examples related to the topic. Then the next step was to study and group out questions from both PT2 and PT4, believe me there are about 15-20 questions types that are common in all three exams (and the one I took on Friday the thirteen) I call them freebies. So when you get to the math section all you have to do is to think little harder for the other 20-25 questions. Let me tell you for the probability questions, in my case I skipped couple that appeared new to me and did the once that I seen similar in the PT's. A question that is 3 lines long with a table I would skip that too.
For Biology, mine was easier than PT4 and similar to PT3 maybe little easy. But definitely study all questions and the explanation for each.
It was fun doing all three science sections, I wasn't stressed out or anything. Basically everything made sense to me. I'm thinking to write it again for the hope of getting easy verbal and/or RC section and boast up my score
Oh one more thing, if you think you did poorly and decided not to submit your scores make sure you go home and write the words/questions types/concepts for each section. Do it right the way, otherwise you will forget them. I tell you, they will come in handy the next time you do your exam and obviously be gain more confidence.
Good luck to all of ya, really wish you all the best