Do the codelab, it can help at times. Look over what you covered that week or the week before to be ready for lab quizzes. START THE PROGRAMS EARLY AND DON'T THINK YOU CAN DO THEM ALL ON THE LAST NIGHT. I learned that one the hard way. Look over old exams a lot for midterms and the final since most of the stuff is on the old exams. Don't be afraid to talk to the professor or the TAs outside of class. I highly recommend going to lectures because even if you know what he is talking about he can really help you understand it more and he give exam hints for almost all the exams.