Do you guys have any tips on how to study for Computer Science tests??

Hi, I am a freshman and I already took the fundamentals of computer science course before high school and currently I'm taking Computer Science 1 and in 10th grade I'm gonna take Computer Science 2. Anyways back to Computer Science 1, because that's what I mainly came here to talk about. Can you please give me tips on how to study for the tests cause every two chapters we have a test and I haven't been doing so well on them, so if y'all could give me some tips on how to study for these tests that'd be great. Also Computer Science 1 is all about Java for us in case you don't know what Computer Science 1 has to offer.