What you need: Rear View Spy Sunglasses, $13 

Risk Level: High

This tip requires two people: One person who either knows the material on the exam or is cheating, and the person looking back at that person. Of course, this method is relying on the fact that your proctor will let you wear sun glasses while taking test. But if they do, you have your friend take the test behind you while covertly signaling the answers to you. It’d help if the two of you set up an easy code beforehand.