Do as many past exam papers as possible.
Maths requires practice. Sure, spend time going over the concepts and preparing notes but spend MOST of our time on doing questions.
Do plenty of practice exams (use what your teacher has given you) and refer to the worked solutions if you get stuck.
Once you have done a lot of previous papers and you are generally feeling more comfortable with the questions, now you need to practise DOING exams. Doing well in an Exam is an entirely separate skill from being good at Maths. In fact, renowned mathematical geniuses have been known to FAIL exams: primarily because of the time constraint but there are other reasons as well.
So sit yourself down, bring back that timer, get a previous VCAA exam that you haven’t done before and do it under exam conditions. Make it as similar to a real exam as possible: no breaks, no interruptions and, if convenient, put yourself in an unfamiliar study environment. Make it as similar to the real thing as possible. The more you do this, the better you will be at performing in exams.