I studied consistently throughout the year rather than doing large amounts of study in short periods of time. So for example I would study a few hours a day during the holidays as well, compared to just taking a break in that time period. That particularly helped me be ahead when I studied in the Christmas holidays period and improved my marks as I also did quite a bit of exam questions during that time. I ended up finishing notes for the next 2 modules for all my subjects apart from English which I just fixed essays on. Study routine is quite important but I also had a natural academic ability in my subjects so I was able to self-study, understand the content and write notes before in advance. So basically I spent the rest of the year just doing exam questions and improving my knowledge, rather than wasting time making notes during term.
This question is a bit dependent on the personality of the person and what they characterise as having a life and their goals post HSC. I had a lot of friends and was well known in my school year, but my immediate friend group we were all very focused to our academics and ambitions so we didn't really do things like have parties etc. That was just something in our personality I guess which we didn't do those kinds of things. We did go sometimes in holidays and stuff to movies etc. so yeah I would say I had a life but you have to make sacrifices during HSC year, you can go out, party etc. after HSC once you get to uni. That was particularly important kind of thought process for me because I was aiming to get scholarships and had goals of doing a phd, so the sacrifice was worth it, as now basically my degree is almost free.
In terms of managing it, it's obviously going to be a stressful year particularly during the exam periods and getting marks back. There's not much you can change about that and I would be lying if I didn't say it was stressful because it was very stressful. I was confident in my preparation so that was one way to manage it, since the HSC is not really something where they are going to throw you insanely different things each year. If you prepare to the syllabus and know your stuff you will probably perform well. Also, the culture in my school was one where we collaborated a lot and I had a good friend circle where we shared feedback and things, so that was quite helpful.