Why your revision is not working- Lillian Mose Newstead Wood

I know exactly what it is like to spend all your time and energy revising for exams, only to forget everything you have learned the second you are handed your paper,or to revise completely the wrong things, or, as is most common, to think you have completed the test to the best of your abilities only to achieve mediocre results. It is frustrating, so how can we overcome this?