Teaching other people about things you have recently learnt is one of the most effective ways of retaining information. This shows that you have understood the topic and more importantly, you can impart that knowledge onto others which on your behalf is a good gesture. If you cannot explain key concepts to other students or even back to teachers if they ask you, then there should be light bulbs going off inside your head that you don’t understand the topic completely. If this is the case, go over it again and make notes on the difficult aspects of the topic that are baffling you. Teaching people will also give you confidence in your abilities and confidence should be one of your traits going into an exam because it is this confidence that will propel you into success. Bit of a cliché but it is absolutely true so take time to try and teach others what you have learnt because from my personal experience, teaching others means you’re teaching yourself too.