This is the method/process I use to study maths, hasn't failed me yet:
1. Pick a past paper from a particular school, do the whole thing
2. Write down the topics (even better, the specific exercises from your preferred textbook) that you made errors in
3. The next day, study and do some questions from those particular topics/chapters until you are confident again
4. Pick another past paper from a different school the day after and repeat.
Obviously, if your mistakes are just simple little arithmetic errors, then I wouldn't worry about revising those topics. The questions you want to revise are the ones where you take the completely wrong direction in or just don't know how to solve. Repeating this process throughout the term until you get a solid streak of papers you are happy with (for me, this is about 90%+) and you will be more than ready for your next 4u test.
I also watch videos (hsc specific) on the exercise we are going to do in class the night before, maybe attempt a few questions.