You won't have to really do much to prepare for your first term. Mainly just figure out when your assignments and exams are and make a plan as to how you are going to study. Apart from that the first term won't be too different from year 11. The main thing though that I feel helped me a lot in year 12 was going ahead in the Christmas holidays because you have like 2 months where you can just go at your own pace and learn the material using a textbook or something similar. If you are thinking of getting a high 90 ATAR then this will give you a good advantage. this doesn't mean for that whole holidays you should be studying 10 hours a day but what I did was like I would try to do between 3-4 hrs a day and all that work adds up over 2 months and you still get to somewhat enjoy your holiday because u are only studying a small part of the day. It helps because when you go back to school you will already have an understanding of the material and will have less stress during the school year because you don't have to try learn content and do assignments at same time. You don't have to do that for every subject but it really helped me in maths and sciences