I suck at standardized tests so I studied for like 3 months. I used the Dr. Collins packet, McGraw Hill PCAT, Kaplan PCAT book, and I bought the 3 practice tests. I also bought the PCAT destroyer, I strongly advise against it, it was a waste of money and the questions were a lot harder than questions on the actual pcat and the focus was really too broad to actually be helpful, but I did like the math portion of the book. The McGraw HIll book has good sections for bio and chem and I think Kaplan is a little too in depth, but I used it as a reference and more to skim over the concepts. Dr. Collins was the most helpful, it had questions that were very much like the actual pcat.