I've just read the first part of this whole thread, and this is my 2 cents.
Firstly it is amazing that you are working so hard this early on. Some people were concerned about the fact that you would burn out, but this is what my mentor told me when I was doing HSC to keep me motivated "Burning out is the excuse that white boys spread around because they can't compete. There is no such thing as burning out". I know what he said was racist, but he was one of 3 curries in a predominately white GPS school about 10 years ago (he's a surgeon now). In terms of state ranking, it is really important that you rank 1st in your school. In my experiences, sure I topped chemistry, but I could have also topped MX1 if it wasn't for my assessment marks. I was the only one to get 100 as my Exam mark and 99 as my Assessment Mark because I was ranked 3rd at school (and I used to go tutoring with the guy who topped MX1 and he knew that I was better than him).
I know that trials should be over now, and your school rankings are finalised. The only advice I can give you now is spam past papers and work on your English. I have almost 3 cartons of MX2 papers with my worked solutions in my garage, and if English is your weakest subject it will most certainly drag you down (English was my lowest mark at 94) but if everything else is high enough you can sort of cover it. I've heard that a HSC mark of 92 in English is the point of no scaling so you would wanna get above 92 at least (but im not too sure about this).
And seriously, do not buy english essays, that is the saddest thing you could do. You are disadvantaging yourself by copying or melding someone else ideas. if the idea is yours, you can adapt it anyway you need to, and express it in anyway that is required. The trick is being to able to decipher the lingo in the exam question and extract exactly what they want, and adapt what you know to the question. English is not really about what you say (to an extent), but rather how you say it, and the meaning that is conveyed. it is the impression that is left upon the marker gets you 20/20, rather than a flawless essay that ticks all the boxes but is otherwise boring to read. Originality is highly rewarded in English.
The last bit of advice I can give you is to listen to your teachers. My physics teacher in year 12 was considered the worst teacher in the school because he was so dull and boring. But I listened to him anyway, and even though I had my notes ready by Feb (like what you were doing), the information that I was able to extract from him was invaluable and the process of collating his knowledge into my notes took my until my trials. For example, here is a question you can think about, "Discuss the relationship between thought and reality" (8 marks). If you think this is beyond the scope of the syllabus, it's under relativity topic in space in the third column XD.