As you are studying for the exam, you pull out a piece of paper and write down your main concepts. Now you go to a friend or sibling and ask them if you can teach them what you just learnt. Now imagine that they are a little kid, and keep your explanations as simple as possible. While you are teaching, tell them to ask questions and help you find gaps in your knowlage. You now review these gaps and you are ready to take the test!