Most students can afford no more than two of them for recreation, but may wish to use different evenings on different weeks. Schedule a regular weekly period when you will review the work in each of your courses and be sure you are up to date. This review should be cumulative, covering briefly all the work done thus far in the semester. Organize your notes in a question and answer form, and think in terms of questions and answers about the main ideas of the material as you review weekly. When preparing for exams, try to predict the questions the instructor may ask.
Good notes are the best bases for review.
Watch for key ideas in lectures and try to express them in your own words in your notes. Know when assignments are given and when they are due.