Repetition and having conservations with yourself or an imaginary audience in regard to the material.
Excellent advice, as a large amount of biology is memorization; I myself made flash cards and used digital flash cards (Anki), also highlighted pertinent information in PPTs and texts, then re-reading those highlights aloud, explaining the conceptual stuff to myself. When doing flash cards I would not simply think the answer and check, I would say aloud the answer/list/explanation, etc before double checking the answer. One thing that never really worked for me, but many people I knew did, was re-write out notes, somehow re-writing helped them.
I know this is old and common advice, but I"ll say it anyway: study over time, whenever you can and with frequent breaks; there's nothing wrong with doing some hardcore study sessions before exams, but if those sessions are just big cram sessions without any studying beforehand, you won't do as well. Over time you'll probably retain better as well, which will benefit you for the MCAT to some degree.
Before you even decide to major in biology, you should really think about whether or not you're actually interested in it. You may not know until after you've taken the introductory sequence. If you do decide to stick with it, make sure to apply the same "am I interested in it?" method to picking which upper level courses you take; also looking over specifically recommended course lists by medical schools helps in that process. The more interest you have, the more easily you'll take in the information and retain it.
If it's possible, spread out when you take your BA/BS required courses that are non-science. This way you won't end up taking 5 difficult sciences courses the same semester (you need to keep up a decent course load, but more importantly you need to do well and maintain a strong GPA). Personally, I did half my chemistries during summer sessions, this way I freed up space during the normal semester and wasn't overly bogged down. You may or may not be able to do this or even want to, it was just what made things easier for me.
Finally, if you have the freedom/flexibility, take your classes (especially the ones where you feel lecture may be most important, or lab for that matter) during times of the day that you will be at your best. I was fortunate enough to take all my bio courses in the late afternoon or evening, which I knew was best for me.
