This might seem like a dumb tip but always READ THE QUESTION. I find that highlighting the directive term (i.e. Evaluate, Assess etc.) and other key bits of information in the question allows me to hone in on those ideas and always refer back to them. For my study, my note-taking technique was pretty much to create three broad themes corresponding to the text I was reading, and then put 3-5 quotes underneath each relevant theme. Under each individual theme, I'd have a small line stating what techniques are used, a line following the techniques to explore the effect of the technique on the quote, and the quote itself in reference to context [if relevant] (i.e. the way a quote challenges/accepts contextual values in creating meaning). All I did in regards to studying was put these notes together, and then memorise my quotes and a bit of analysis. (Techniques often spring to memory naturally, but you can memorise them if need be)
In the exam, I would spend a minute or two forming my thesis and connecting all my ideas to the question. From this, I'd then go into my essay, and apply 2-4 quotes (normally 3) from each theme which were most relevant to the question.
The key for succeeding in English is practise. The more practise you do, the more comfortable you'll feel with unseen questions. If you don't feel that your English teacher is helping you, see if you can speak to the head of English or another English teacher who can help you. I have a couple of friends who would memorise their essay, but I wouldn't recommend it considering how easy it is to forget a part of the essay and then completely mess up the rest of it.
These tips helped me get through HSC English relatively smoothly, so I hope that they are helpful for you too!