A good explanation of AQA triple science up there.
I'm doing all 9 exams this June 2015 series :3. I haven't done much revision as science is generally a strength; in previous mocks I dedicated around a night or a weekend to ineffective science revision, but still got A*s pretty much everytime, sometimes highest mark in the year.
My advise: practice papers, just do them 10x over, the week before, or the year before - you'll be golden either way.