Eng Adv: Take yr 11 as an opportunity to really consolidate your essay writing skills. Also, if your a rote-learner (i.e, you memorise essays then regurgitate them in exams), get out of this habbit, because remember they can ask anything in the HSC.
Eng Ext: One of the things I noticed with this course is the standard of writing is extremely high. It is unlike adv where you can get away with somes substance but sophisticated language. In Ext, you really need to know what you are talking about, and demonstate a personal engagement with the texts. Here we come to another crucial point that really applies to all extensions: ONLY STICK WITH IT IF YOUR PREPARED TO WORK HARD AND HAVE NATURAL APTITUDE. To give you an idea of how difficult the ext's are/ how many people choose it when they're not capable of it, the eng ext course at my school had 56 peopele at the start of yr 11. We now have 22. Similarly, Maths Ext began with 134. They now have 63.
Maths: Irrespective of what level your doing, teh best bit of advice I can give you is KEEP UP TO DATE WITH HOMEWORK. Remember in maths especially, the foundation of yr 12 content and skills is set in Yr 11.
Sciences: In Biology, prepare for shit-boring topics on plants and ecosystems. In all sciences, make sure you cultivate practical skills, and keep up to date with the syllabus. Also, if your one of these people who just took physics and chemistry to look cool, DROP NOW. Do not assume just because you could do SC science, you a suddenly a science genius. I got band 6 in science SC, yet I can assure you I would not have been capable of physics or chem.
Humanities (Legal, histories): Truly try to understand what is being taught rather than just memorise stuff. This will help you a lot. In Legal Studies, revide consistantly because there is a lot of content. You will also probably find Legal very disjointed to begin with, but it all comes together later. In Modern and Ancient, make sure you get into the habbit of quoting historains and sources from the start. If you are looking for top marks, you should also master the concept of historiography, as the top-range answers in the HSC will, I guarentee you, make use of it.
PDHPE: To not go in there with the misconception that it is a bludge subject. This is WRONG. There is a lot of content that you need to master. For this subject, the syllabus is also very useful. Also, writing in PDHPE is similar to writing in the sciences- concise, and sophisticated in knowledge rather than language.
The Arts: I'm not an expert on what should be done here, but in Drama, ensure you keep up with you log entries, because I hear this will save you A LOT of grief later on.
Good luck everyone, hope that helped.