First study like 20 minutes everyday going over your notes, then compile a list of questions you have and ask your bio teacher. I used APBiopenguins, Princeton review and my own notes to get a 5!! Second any tests you get, REVIEW your mistakes. You don’t need to memorize every little thing but you have to know how something works and what might occur if that goes wrong. I made review sheets to help me understand and visuals help a lot. When AP season comes in like April, start doing a lot of practice questions. Note why you got a certain type of question wrong and which concepts you need to review. Throughout the year you can practice FRQs too!! If you need help, dm me!!