Answer:
Study, ask teachers questions, email, use this app, etc.
Explanation:
If you study for a test/exam. Look over the study guide and recite it for 20 minutes and take a 10 minute break. Then pretend you're explaining the subject to someone for 20 minutes and take a 10 minute break. Then go over the study guide again and see if you missed anything while explaining and then explain it again but this time with the things you missed. Repeat if necessary. Flashcards on quizlet n stuff can help too.