You want to review for the MCAT in the most efficient way. First, review only the topics that will be on the exam. Second, review these exam topics with the test in mind. What this means is that you must do content review in conjunction with working real exam questions.
If you just do content review alone, then you'll end up forgetting most of what you went over. However, if you work MCAT problems while doing content review, you'll retain most of what you learned. Incidentally, the stuff that you retain will be the stuff that will be tested on the MCAT.
There's only so many concepts an introductory course can cover, and there's only so many ways one can test these concepts. So, if you know the aamc topics, and you do enough past MCAT questions, then you'll figure things out.
What this means is that a question may at first appear to be very difficult because of the way it's worded, or because it is given in the context of a strange experiment that you've never heard before. But then you'll realize that the MCAT doesn't test you on strange experiments that are not covered in a basic introductory course. After realizing this, you'll be able to see right through the strange experiment and realize that the question is simply testing you on some very basic concept, like Le Chatelier's principle, just disguised in the context of some unfamiliar situation.
To sum things up, review for the MCAT effectively by going over the official test topics published by the AAMC. Use the online notes here to guide your studies. And remember, do not wait until the last minute to take past MCAT exams. Start doing MCAT questions as early as possible, in conjunction with content review. Have fun reviewing for the MCAT!
Physical Sciences Section
General Chemistry Review
Electronic Structure and Periodic Table
Bonding
Phases and Phase Equilibria
Stoichiometry
Thermodynamics and Thermochemistry
Rate Processes in Chemical Reactions - Kinetics and Equlibrium