I know it may seem tedious, but really know your texts inside out! It's important to not only reread your texts but to analyse different themes and perspectives when rereading. By that, I mean being able to know your text, its context, characters and underlying messages well enough to be able to apply these to different prompts you might encounter. Don't be afraid to annotate, highlight, tear your book inside out
(a bit of an exaggeration, but I had to actually do that for one of my texts so I could annotate it easier) in order to fully explore and understand all the complexities and details of your text!
For SACs, I really recommend brainstorming potential prompts that are really different from one another, so once you either plan or write essays for them, you at least have a foundation of ideas you can explore if you were to encounter a similar prompt in the SAC. I personally also advise against memorising, just because it can make your essay really restrictive and you are very likely to not explore all the different perspectives of the given prompt! Some quote and sentence memorisation is fine, although I believe the best thing (for me personally) is to plan ideas that are applicable to numerous prompts.
I also cannot stress enough how important timed essays are!! This by far was my biggest challenge, and I made the mistake of not handwriting or timing my essays whenever I did essay practice for my SACs. So by the time the English exam came around, it was the most emotionally taxing and stressful experience during my time in VCE, since I was terrified of all my work for English going down the drain because I was so overwhelmed by the exam's time restrictions. For a 35+ (and above also), it's not necessary to write an essay every single week, but make sure to get consistent practice by writing essays or at least planning for certain prompts on a routinely basis. This is one of the best ways to refine and improve your writing, in my opinion!
Most of all, don't be afraid to interpret your texts in your own way,
as long as you provide evidence to back it up. If you're able to have unique ideas or perspectives of the text that can be proven or backed up from evidence in the text, this will really set you apart from other students and put you in the upper range of English students.
Feel free to shoot any questions and apologies if this was wordy! Hopefully this helped