Hello fellow drama student! So how I've been going about prepping for my theory assessments (it's been working well so far!) is basically how I would prepare for English, but with a few altercations.
First off, I look at the rubric to see what is required of me to really understand what the markers are after; for example, I'm studying Significant Plays of the 21st Century which is basically looking at the influences these plays had- how they've broken new ground and how it impacts the audience in
powerful ways. Relating this back to English, it's kind of like looking at discovery and realising that the questions will always relate back to how discoveries are far reaching and have the potential to change the broader society. If you can really understand what they're looking for, you should be ok!
With me, I like to make sure that I REALLY know my text so I would suggesting having a really thorough read over them and after that, pick out the themes which the plays explore. For example, The Laramie Project was composed under the premise of Matthew Shepard's brutal torture and murder in order to explore issues of homosexuality, religion, class, economics, etc, etc through the raw responses of those interviewed.
So after Extrapolating your themes (and this is something I swear by) Make table for each theme you come across and providing 3 pieces of evidence for each theme + its effect on the audience. (Also remember that evidence can be either from the play itself, an actual production you have seen; whether it's experimental learning or if you've actually gone out to watch the play, and also an imagined production. If you plan to use an imagined production- place yourself in the shoes of the director, set designer, etc. The thing about drama essays is that sometimes, they require you to be quite creative with your response).
This is the main thing I study before walking into any written exam and the reason I say this is because, whilst I do have a general essay scaffold, it would be a HUGE mistake to memorise it word for word because the questions can get pretty unpredictable. I've seen past papers where they literally give you a stage and they ask you to explain how you would use the space- but of course, if you're AMAZING at changing your pre-memorised essay on the go, then by all means, DO IT! Me on the other hand, I tend to treat Drama as I would with Module B in Advanced English and in my opinion, it's just safer to have a comprehensive understanding of your texts.
Last thing you can really do is practice! Look at past HSC questions and attempt to mould your general scaffold + all that good stuff table you wrote previously into the table. I know it's not a simple solution, but Drama really is challenging in its own way!