I got a 520 this past May. I took a MCAT prep class through my school, but the only real benefit I got from that were complementary practice exams at the beginning and end of the course. I studied outside the course on my own a bit that semester, but not much. Mostly going over areas I knew I had trouble with, like physics and parts of psych/sociology that I hadn't learned in the introductory classes I took. I never touched CARS, because I've always excelled at reading comp. This might not be the same for you, but it's important to know what areas you're rock-solid, because you can leave those areas alone (save for on practice FLs) and save yourself a ton of time. It's also important to know where you struggle most. I'm a neurobio major and have always excelled in biology classes, so I could brush over that lightly. I needed a touch-up on gen chem (I used AP credits and went straight to orgo), but nothing serious. But physics, interesting as I found it, was always a battle. So I used Kaplan MCAT practice books for physics. I got help from an engineering friend. I watched Kahn Academy videos on electricity and magnetism.
When I got home from that semester (I took the May 20th date), I spent two weeks studying my ass off on all the things I was still unsure of, and took plenty of practice FLs. It was like MCAT boot camp. It was exhausting. But it paid off.
TLDR: know what you know, and know what you don't. You don't need to dedicate equal time to biology and physics if you've never gotten below an A on a bio exam but physics just throws you for a loop every time. Be smart. Know yourself. Good luck.
