Bibliii
Make sure you have all the basics down pat, and understand what equations to ise when. Check if your library has any resources like the Oxford Study Buddy or ATARnotes topic tests. I found it really helped me. Understand your formula sheet, and write down any formulas that aren't on there, like the general equation of a sine or cosine function, things that are usueful. Use this when you are studying.
With math, the only way to actually study is by practicing. Practice heaps. Check out the QCAA exam examples. Recycle through different textbook questions - the cambridge one has really good ones. Talk to your school or local librarian and ask if they have year 12 methods resources - it always helps. You could check out the VCAA and HSC past exams, and pick out the ones that are relevant.
Hope this helped,
-jinx_58