Is standard australian english the most prestigious in all situations? Can other varieties be better to use?
Obviously a lot of the time SAE is and you would want to use it (say why).
There are also a lot of situations where you obviously *wouldn't* want to use it. Do you use full sentences every single time when talking to your mates? This also goes off into stuff like in some groups you'd look like you were being a pretentious snob if you used standard language.
By the end of the year you'll know the basic ideas from which all essays are based and know the general case to argue (eg you *could* say SAE remains the most prestigious but I found at least that I had a certain formulated opinion of everything which wasn't exactly mine). It'll probably take you days to write up an essay now but by the end of the year you will be able to churn them out in 55 minutes like you need to (only to promptly forget all your examples again like I have)
Oh thats the other thing - include examples. Preferably not the same ones that appear in the Heinemann text book (as nearly everyone has that) but you don't have to be all fancy complicated with them, just be slightly different. If they sound stupid and obvious, include them anyway.
I don't know how many essays you've done so far: "In your response, you are expected to demonstrate your ability to use relevant descriptive and metalingustic tools. You will need to refer to at least 3 subsystems of language." essentially translates to 'Use metalanguage. Don't forget there are things outside the discourse' (there is more than simply the words people use). Not all the time it will be appropriate to include all of them, don't go absolutely nuts trying to cover them evenly, but you can see how you could include non standard pronunciation and syntax etc for a few sentences.
I hope a bit of that helps. If you need ideas I can go dig up my book and have a squiz for stuff.