For biology, make sure that you actually understand everything within the notes, EVERYTHING. The exams in biology test your application of knowledge, so merely being able to spew out information is not good enough. Do lots and lots of past papers, take your time in the first few, and then do the rest under timed conditions. If you are unsure of how to answer a question, attempt it anyway as you would in an exam. Also, make sure that you ask your teacher to mark your answers - you could have some problems with the structuring of your responses, etc.