Check out the yr 12 syllabus for your selected subjects and the dotpoints, see if there have been any recent syllabus changes eg Eng adv changed in 2018 so new syllabus stuff begins with the 2019 hsc paper ect.
This stuff below you can even start after you've completely learnt all your prelim content and you'll still be fine
Practise HSC past papers based on your subjects and work from your weaknesses (even if you don't know the content, find the solutions and pick up how they respond to the question, also try and identify patterns in the types of questions they try to ask), Also if your school has access to edrolo maximise and memorise as soon as possible cause it will really help if u start early, though around term 2 is a good time to be working on your notes so don't stress (though still make them throughout the year). These are the stuff I started doing at the start of year twelve and kind of dropped the ball throughout the year and I wish I had sustained throughout because it's probably the best way to study (in my opinion)
and by all accounts get as much practise as you can cause yr 12 flies. But enjoy it and stay relaxed!
Good luck!