Managing the workload becomes much easier if you use your studies and ‘frees’ efficiently. It is easy to think you can use that time to socialise and do it at home but it is important to distinguish school as your work space and home as a more relaxed space because that will really help your mental well-being.
Revision techniques will vary between students. You may use the technique you found most useful last year, and judge its validity on the results it brings you. The following attachments are extremely useful to you and are designed to help you succeed:
How to study for your exams
Here is a good starting place for your revision and studies: Evidence based tips to help learners