I think the thing that really helped me in Biology was taking a Biochemistry course that was strictly problem solving in nature. There was no rote memorization. It taught me the strategies necessary to deconstruct the passages. If this ain't an option for you, then I would suggest picking up a scientific journal and trying to read for understanding. That was another tool that helped me out. As for the Organic Chem, I just read over the Kaplan review book the week before the test to refresh my memory. Good luck!
I don't really have a strategy. I asked ke-ke for more info - need to know where you are at, how you've been studyin etc. Basically, I think you need master the basic scienceforst before attempting to do tons of practice problems. That doesn't mean don't do any practie passages before mastering them, but to save the bulk of those for when you have a good command of the sciences.
Bio is much more reading comp these days so def. read the passage. I think the hardest part is to figure out what they are asking you (it's always something basic). There isn't much org on it either, I think its 4 passages out of 11. And it is very basic orgo: functional group chemistry. Don't be intimidated by large structures, just recognize the functional groups and how they are changing.
Lastly, advice is only advice. Different things will work for different ppl. I always say that your mcat score is not up to the prep comnpany or even the book you use, it is up to YOU.