Firstly, I recommend that you try and set yourself some goals, as in ranks and marks you would like to achieve in your subjects. Try to be realistic, meaning everyone always says I'm aiming for 99.95, but that is a very off chance for most people, so that you have goals that you are working toward throughout the year.
Main thing though is to have consistency throughout the year (not as important in year 11 as they probably mark easier and you have less exams), but just try to do constant study as in like a few hours a week (doesn't have to be like every single night working all night, as you should have some balance with like playing a sport, exercising, or just spending time on Facebook, youtube etc.), and you won't have to worry about the struggles of cramming and just trying to know the basics because you don't have enough time left. However, when you come to like 1 to 2 weeks before the exams that is the time you have to try focus a lot as small details in answers are the difference between getting a band 5 and band 6 in many subjects especially the sciences.
If you do that and have some intelligence honestly you can easily get above 95 ATAR, and much higher if you are talented in your subjects.
Lastly, after you learn the content from textbook, videos etc. make sure to attempt past paper questions and mark yourself or ask your teacher to do it. A good way I found was to study with friends like we would send each other questions we saw in exams that were tricky and it helped improve us as a cohort. Also, after you get an exam result back if its not great, don't just try to forget about it and not look at it again. Analyse why you lost the marks (might be good to ask the teacher for a copy of the marking guidelines and to read your friends' responses that might have scored well)
For subject specific advice:
maths:do textbook questions to learnt the basic content, and then move onto past papers to improve your overall ability to approach exam style questions and your exam speed as finishing some ext 1 exams can be difficult if you haven't already practiced working at a fast pace. for tutoring you might want to get one, but as long as you do the above things and work with your teacher probably not necessary.
Adv English: Unless your teacher will mark like a lot of your essays for you consistently, then I would probably try to get a private tutor for this subject if you are trying to aim for a 99+ atar. For English I did a lot of research on the texts (not just what teachers say to read it twice or whatever) like looking at ideas and analysing it in a way that flowed well with good language and specific quotes and techniques, wasn't generic (everyone tends to use the same type of arguments for example like in mod A that texts show the value of the context, but you have to try and show it in a way that addresses different parts of the rubric like the importance of techniques specific to a text type i.e. camera and lighting stuff for movies and for a play like asides and stuff, making direct distinctions between like the type of language used. for instance in Shakespeare King Richard he uses christian imagery and demons and stuff, while Pacino in looking for Richard looks at the same theme of manipulation and power but addresses it through the characters becoming politicians so he can relate the text to his specific audience which is American people, while in Shakespeare's its English 16th century. So pretty much by paying attention to these kinds of things, no matter what the question is on the exam day you should be able to adapt ur essay to the question because you have based on essay on the rubric and the ideas that link to that rather than just random themes that might link, because the question most of the time is just a straight sentence from the rubric with maybe a quote from somewhere else
For short answers, honestly didn't do that much study apart from memorising techniques and knowing key phrases from the discovery rubric, because if you have already like written essays from scratch using quotes and techniques for other sections, you already know how to analyse a text and just have to do that on a smaller scale with the texts they give u.
For biology, I didn't do the subject but I did do the other two sciences and I found that making your own notes using like textbooks and other band 6 students notes, based on having a dot point as a heading and then writing information beneath worked well. Past papers are pretty important too as you see the type of detail you need in answers to get good marks
For the chemistry and physics:
http://community.boredofstudies.org/17/chemistry/354315/band-6-a.html#post7197320