Totally understand how you feel, you pretty much sound exactly like me this time last year, just wanted to get English over with and concentrate on the maths/science subjects I really liked. While I can't really give any A+ VCE English exam advice, I'll give my best advice ... (I honestly feel I never truly "got" it, but worked hard enough/stored my brain with enough knowledge to score a raw 38).
Can't say anything about comparative text as I've never studied it, but for the single text essay I'd just say make sure you have a good supply of quotes that could be relevant memorised for the exam , and pick the topic you're most familiar with, and make sure every paragraph addresses this directly (if it helps, write down the relevant quotes from your head at the start of writing time) - as everyone told me, most important thing is directly addressing this question. I'd also suggest in some sense "studying" a thesaurus to get relevant varied/interesting/sophicated vocab (but make sure you use it correctly!!!)
For language analysis (probably my best section), don't focus on individual techniques, rather choose a main ideas/arguments to focus on per paragraph, and pick out 2 or 3 techniques that work together to pursuade of this particular argument. And don't forget about the picture, treat it as any other technique(, so discuss the picture in conjunction with some other technique that all relate to some key idea or argument that author makes).
That being said, for a 30 raw you'd probably need around 5-6s assuming you're about average in cohort, so you're probably not too far behind as of now, just try to take on any feedback you get, and bring all the knowledge you accumulated over the year into the exam. Also, if you don't get the 30, there's heaps of other ways through transfers ect; I enquired about a transfer a few months ago for next year, and after 1 year ATAR/VCE is irrelevant; just a pathway that will make your life slightly easier. Best of luck for the exam and future studies