I feel that, in my school, calculus (both AB and BC) was either a total hit or a total miss for the student body. The best advice is to get on the train early... You will learn the basic foundations of calculus within the first few weeks (power rule, chain rule, explicit/implicit differentiation etc...). Know these like the back of your hand or I can promise you will be screwed beyond belief. Other than that, study your notes a few days before exams, buy a practice book if you want and do problems from there.
I took AB, and felt that I should've taken BC but for some reason my guidance counselor didn't want me taking it. But, my guidance counselor is the same woman who told me I'd only get into a low level state school or community college 🙄 Stupid woman.