Before any exam try to solve the previous year's paper and test yourself on where you stand at the moment.
Prioritize your task before any fun activity, do the most important task on the priority.
Take breaks between studies which will relax your mind, and after that, you will be able to do the work with more focus.
Reward something to yourself when you achieve or get good marks on a test.
Set realistic goals that you can achieve, do not pressurize yourself, make a goal for each day, and try to achieve that.
Sleep is one of the most important factors in the life of a topper student, so get a long and proper night's sleep.
Focus on the mistakes you make and do not repeat them again and again.