I studied for my AS English Lit the night before the exam, and got an A. I also did A Streetcar Named Desire!
You sound like you're pretty prepared already! More prepared than I was anyways. I would say just make sure you have numerous quotes per character and per theme memorised, you most likely do if you've done a lot of essay plans/essays. Make sure you also have a few obscure techniques that your teacher will likely have mentioned as well as context, which is heavily important. Try incorporate at least a bit of context in each paragraph.
Also definitions! Such as a tragic hero, etc. If your question includes it, or you want to make a point about it, it's always preferred if you have a definition which you can use to validate your point. Or, if it's in the question, it's good to have the definition to use in your introduction. I suspect you know this already, though.
As long as you understand the play, have quotations, context, techniques and include arguments and counter-arguments whilst conveying your point strongly, I'd say you've banked an A already. You sound super prepared already so don't stress, just trust yourself. Hard work will reward you.