tbh the only thing I recommend for maths preparation is to keep doing past papers. That's really all there is to maths and that's why if you let it, maths can be a very enjoyable subject during your hsc. Most of the questions in past papers are the same if you familiarise yourself with them. I understand you're in prelim and things may be a little different to hsc.
Also, make sure you're not using a basic textbook like maths in focus (I get a feeling that you aren't using it anyway), but just a heads up. Also, learning in advance is quite helpful especially for a subject like maths where you can then consolidate your understanding of a topic and it's theory. Another thing is to understand and not rote - like you just can't rote maths, it wont work out in the end. To tackle the harder questions at the end of an exam paper requires a good understanding of maths and its concepts - that's what they're testing.
So if you break it down: learn ahead, understand what you're learning and learn it well, use a decent textbook like Cambridge + Fitzpatrick as a supplement and avoid maths in focus, do countless past papers PROGRESSIVELY (no use leaving past papers until the last day or even the last week before an exam - you need to be doing it continually to let it sink in) and do the questions on all of the topics that you have covered so far (this pretty much means that if you've done like 4 topics already, don't only focus on the latest one when you're doing past papers but actually do the questions on all 4 of them to keep your maths skills up to date otherwise there is a tendency to forget some parts of maths and trust me it's hard to relearn it if you've completely forgotten it - so keep practising.