Here are some tips:
If you are really serious about studying, try and aim for six hours a day.
Split this up into 1 hours slots per subject, so you don't tire and get bored, and allow yourself 10minute breaks (run around outside, snack, whatever) between each "session" to give yourself some extra energy.
It may help getting up early (as if you were just normally going to school) at around 6/7am.. which means you will have finished your whole 6 hours of studying per day by 1pm - lunchtime! So you now have the whole day AND the whole night to relax, do whatever!
Otherwise, if you work the other way around (not morning person) or have a job during the day or something, just shift your six hours down to the end of the day/night, but only if you work better at that time.
Try to stick to the 6 hours, you will be amazed how much you get done! It also means by the end of the holidays you will have 126 hours of study done... this puts you ahead of the rest! AND you've been able to enjoy heaps of time off!
This is what I do, except I shift my time so I get a sleep in but still finish around the afternoon time. Then i just go out pretty much every night. Works for me! This should definately help get your ranks up, as well as get you into a good pattern of study for the HSC.
In regards to notes, I would suggest going through the syllabus (I don't do any of your subjects so I'm not much help) to get your headings, then simply summarising your textbook. This may seem like a daunting task, but just split it up into dot point sessions. I do this for Modern History, and by the end of a couple of days I'm amazed that I have actually summaried the whole textbook!
Practice Essays and Papers, especially for Maths, is really helpful. For the essays, make sure u practice while abiding to the time limit, but make sure you dont overdo the writing! Cause I did for half yearlys and managed to get RSI in my hand right in the middle of exams! Lol..
I don't actually start trying to memorise the notes until the week before the exams, as I find just writing them and practicing/memorising essays more helpful. But whatever works for you, I'm a visual learner and you may not be.
So yeah, hope that helps. Good luck on acheiving your aims!
Beth x