I like flash cards for MCAT material. That way I can put it in a "fill in the blank" or "vocab" format, and easily figure out what I'm forgetting. It's a good trick for bio, especially when it comes to hormones or amino acids. It may help with memorizing formulas in Physics.
When it comes to GenChem, OChem, and the conceptual part of Physics, you'll have to figure out what works for you. I made flash cards even out of concepts for myself. Kaplan did a great job with their recent set by providing flash cards (I received these from being in their class). It DEFINITELY comes in handy when I'm sitting in the car on the way somewhere and have time to pull them out. It's great study-on-the-go work.
Other than that, just lots of practice problems immediately after learning the material. Often times that is the best way to get the info to "sink in". You'll learn a concept, do a passage on it, get an answer wrong, and you'll fine tune your understanding of it better.
Hope that helps!