Sorry if I'm late to the party
1. How much time did you spend on english, and what did you do?
A lot, approximately 200 hrs minimum writing the first draft of my Mod A (according to Microsoft Word file properties) to the best of my ability (I don't see why people make first draft 'bad' when they can go for perfection first time around), this multiplied by 5 for each of my memorised scripts (2 Aos, 3 Modules) should be 1000 hours already, then you need to factor in the time I spent practicing my adaptation for which there is no official timekeeper but I reckon it was at least 50hrs per script, currently the total is 1250 hrs minimum-then you need to include the time I spent refining the drafts, researching context etc and then memorising 5000 words.
Was it worth it? Absolutely, would not do anything different. You only get out what you put in.
Now for my own approach to English, the most important thing you should get your hands on is a high achieving private tutor who has done your text for their own HSC-imo there is no point in hiring a tutor who has completed for YOUR TEXTS for the HSC regardless of whether they have extraordinary marks or have 'read and done analysis on' the novel (which simply in not enough as they still do not know the 'ins and outs' in exam technique as they have not written/practiced adapting essays to the set texts nor have they faced any of the problems that you will most likely go through as it is specific for each text-same applies to looking for HSC markers/school teachers as they most likely did not completed the HSC with those texts and have simply gone to a few bridging courses to teach it). The tutor you seek also has to be willing to make your responses/scripts as there is no point if they don't do so-try get one that gives fast feedback and does not delay your essay marking for weeks and weeks because of 'uni commitments or school commitments). Next up the 2nd most important thing to my approach was to read exemplar state ranking/High Band 6 essays to learn how to write a high level. Other than that, it was all 'grind' in writing essays/memorising/adapting, also if you haven't noticed I did Memorise my scripts because this is the most fool proof way to score high marks and it is really not that dangerous (in not directly answering the question) if you practice enough. I could have easily not memorised but there's no way my expression made up in 40mins exam time beats someone who memorises and answers the questions (by not memorising you only seek to beat people who memorise and neglect adaptation and it is sometimes even more dangerous if you just have a torrid 40mins of thinking)
2. What are some things that you need to do in order to understand the texts and modules? I know 'understanding' sounds primitive, but I'm having trouble with that right now. I don't even understand it enough to form a solid thesis, let alone refine and perfect...
You will learn these in time during class. If you want to address these ahead of time and stay ahead of the pack I recommend that you seek private tutoring as it is quite hard to summarise all of these questions in one post.