If I could do the OAT all over again, I would have just done practice tests. I did a free Kaplan one, the two Kaplan tests that come the book (one in the book and one online), and two Princeton Review tests. For the last week of my studies I did nothing but those tests. I wish I had done that for 3 or 4 weeks. I'd do the test in the library under conditions as similar as possible to the real thing (timing, calculator, etc). Then I'd score my test and review every single problem. Why I got it wrong. Why I got it right. Sometimes I'd get it right but for the wrong reasons so you can't just review the wrong answers. So for those 3 weeks I'd recommend you just spend your time doing nothing but practice tests.
However, in the next month you can still squeeze some minor stuff in. I recommend the Kaplan MCAT flash card app for your phone. That was great when I was waiting in line somewhere or just otherwise bored. I had a few other apps. Chemistry, anatomy, etc. It's not focused study time, but if you do it enough it will help you keep random things like equations, hormones, and all that straight for when you start your practice tests.