If no one is available, use a cassette recorder and listen to your recorded lecture. This is a great re-enforcer. After taking comprehensive notes in class, completing assignments, and reading the material, you are now ready to put this information into your long-term memory. Information that is not needed for any considerable length of time stays in the short-term memory. When students wait until the day before a test to cram, the new information they are placing it in is the short-term memory, making recall difficult.
Procrastination can be a real enemy to college students.
Frequent reviews of notes and reading material is the best way to put information into the memory on a more permanent basis. The more often a new skill is practiced, the more proficient you become in that skill. Taking in smaller bits of new information each day provides better retention. Associate what you already know to the new material to create mental cues. Your senses take in knowledge about the world continuously.