I would definitely agree with everything SuperStudent has said.
One thing that I would keep in mind, however, is that different people all learn best through different means. You are in year 11, so you still have some time to play around with different ways of studying before your final year 12 exams. I would really advise you to make the most of this opportunity!
With that said, of course, it's not a bad idea at all to find out how others study, because their strategies might work well for you.
One thing that worked really well for me, was making sure that I fully understood all the content in each class before coming to the next class throughout the year. Since a lot of the content you learn is built upon in further classes, it is very easy to fall behind by not fully understanding just one lesson. Really make sure you are perfectly comfortable with everything you are taught!
Also, you should get a feel for what the SACs at your school are like. If your school has a focus on challenging or non-standard questions, study up on those. If your SACs are easier, just make sure your understanding of the easier concepts is bulletproof. As a whole, of course, you should know every topic and question style very well - this will really help you out next year!
Writing your cheatsheet by going through the textbook, reading and understanding every concept, and condensing all of it to an A4 page is a great way to ensure that you are comfortable with everything you have learnt. If, of course, you are caught off-guard by something you read in the textbook, spend some time revising it before completing your cheatsheet.
That's all from me. Good luck with your exams!