Year 12 here (nearly former Year 12 lol)
Stay on top of any and all holiday homework! I have had stressful nights worrying about getting my homework done because I left it last minute. Sometimes it might be the evidence from homework/coursework tasks that get you your S to pass the subject. It was reassuring to know when I walked into my SACs that I had my S already because of my coursework.
Another piece of advice, have folders to keep activities and any practice SACs that you are allowed to keep, so that way you have resources to look back on to identify areas to focus on.
Year 12 is long and stressful, draft a study plan early on, and plan your time around assessments and exams.
This one is a personal preference but type/print your notes rather than handwriting. I found this gave me more time to do practice papers and pull out key concepts in class while I had access to the teacher. If you do use this method I recommend (depending if the subject warrants it) handwriting your own summaries of the notes and highlighting key parts.
Finally complete practice papers! This is the best way to familiarise the structure of assessments and exams. Ask your teachers to provide papers or questions to practice on and seek that feedback. Plus if doing English practice prompt breakdowns as there is only so many ways VCAA can ask a question. I remember right before my legal exam (I did it last year as an access student) I broke down a 10 mark question with my teacher and the 10 mark on the exam ended up being very close to what I did.
I wish you good luck for your year 12 year, but just remember don't be too hard on yourself if your scores aren't what you expect. There is always going to be a way to get to your career, but it relies on the effort you put in. 😄