Ash444 The best way to improve at English is practice. Write stuff, bad or good, and learn from it. It means writing paragraphs and getting feedback, and then when you get your SAC back, learning from your mistakes and implementing changes in your writing. You won't get anywhere without practice. When it comes to reading the book, I read my books once (although I'd probably read them twice if I was you, 1 for SAC and 1 for exam -> I just felt pretty well-versed in the texts) and instead focuses on analysis of themes, symbols, characters, etc. I tried using online resources, but I also purchased the ATARNotes text guides which were so helpful (worth every cent ahaha). I then practiced adding these elements into my writing. It takes a heap of trial and error, but you might as well write and then improve from there. I also worked on improving my vocab by sing thesaurus and creating word banks for terms I often repeat (e.g. instead of saying "highlights" every time, I could say demonstrates, conveys, delineates, illuminates, depicts, illustrates, emphasises, etc.). I would only look at tutoring if your really struggling.
To get a 45+, you need to be aiming for A+ in all your work, and by A+ I mean 80-90% or so for your SACs and the exam (of course, one or two not so great SACs won't impact it all too much, since the exam is worth the most). At least this is from my experience (again, you just don't know, but getting into the top 2% is really tough). However, please don't focus everything on your grades. Honestly, a 45 is cool but a 30 is awesome too. You're best is good enough, and that doesn't mean working yourself to the ground. It means trying your best, putting in effort, but knowing when enough is enough. There's so much more to life than numbers on a piece of paper/screen. Your wellbeing is so much more important, and enjoying your last years of school whilst studying.