Look at the syllabus for each subject, then coordinate your notes and summaries around that format, using the dot points as headings and groupings for the information. After you have a succinct and comprehensive amount of notes, then look at past papers (from board of studies, or even independent / Catholic trial HSC exams) and then attempt to answer some questions from them.
Though, really over the course of the year you should have been developing notes as you completed each dot point of the syllabus, and then now would be the time for attempting past HSC papers and as such.
For Maths, is more practice practice practice. Learn and revise the concepts you need to complete the questions, and then attempt some past papers or questions from the various text books. (I'm not a Maths student, so you might want to consult some other Mathematicians on this site first. n_n)
Best of luck with the studying. Just do what you have always done, just on a far broader scale and encompass all the areas you have covered in your subjects. If you prepare early, then you'll have enough time to cover everything in-depth!
