To be successful you must spend 2 to 3 hours studying outside of class for every hour in class, more if science is difficult for you. This will help you avoid having to cram for tests. Read the assigned chapters before class so that you will know a little about the topic. Take detailed notes during class, then re-read the chapter in detail, using the study guides to help you pick out the most important topics. Use the study guides along with the self-test described below to prepare for exams.
Some students recopy their notes to study for exams.
A more efficient way to study is to reword your notes as questions. Be sure to have a question for each point discussed in class. Then make an answer key for your questions. To prepare for the exam just go over your self-made test until you make a 100. If you are having difficulty with the material see a tutor.