In response to your question, I studied really hard for the test. I'm currently working full-time which made it even more difficult. Since the test did not have a timeline really helped. I took the test when I felt I was prepared and that translated to 4 months. You should do the same.
As for studying for it, study out of the Kaplan book from front to back. I read the material at least twice and did every problem in the book plus the extra material provided from the Kaplan course. The lectures didnt really help. Finally I did all the TopScore practice tests, making sure that I went over all the explanations, wrong and right, b/c a lot of time I got the right answer for the wrong reasons.
Make up mnemonics for yourself, especially for Bio. Its pure memorization so things like that help. For instance, POSS stands for Pistils, Ovary, Stigma, and Style for all the female parts of a plant. I won't tell you what POSS sounds very similar to. Figure that out for yourself. Likewise, I used FAther, stood for Filament and Anther for the male parts of a plant.
The PAT just takes practice. You should developed your own way of doing this section. I made my own method when i did the hole punching which reduced my time and gave me 100% everytime i did the practice tests. I basically drew a square on a piece of paper and divided it into four sections. Then I placed dots where the holes were as i unfolded the paper in my head. You should try that. Make sure if you do like that method, to make all these squares on your scratch paper b4 you start your test. It really saves time and time is against you in this test. I think playing a lot of video games when i was young helped in this section too. Haha.
Finally, just do as many problems as you can and go over flashcards(provided by kaplan) or ones made by yourself the day before the test. It really rejuved my memory right before I took the test w/o stressing me out. One more thing, taking a test in the morning is the best time to take a test. I took mine at 9:30am. Its been proven that test takers performed better when the same test was administered in the morning as opposed to later in the day.
I thought the PAT was very similar to the practice test from Kaplan and TopScore, although the angle ranking was a little bit harder. The RC section was more difficult merely because of the fact, when I went to the next question, the passage would automatically scroll to the beginning of the passage, making me lose my place. Expect that to happen when you are taking it.
Hope that helped.