know all your points really well and understand what each piece of evidence does
i had 2 generic essays (mod c, aos) and adapted them on the day
mod b was just poem summaries (i do yeats)
memorised a creative I adapted to stimulus (didn't really adapt bc my creative fit the stimulus really well lol)
mod a remembered 6 adaptable essay paragraphs that covered the main themes of frankenblade (fucking stressful would NOT recommend)
usually intros + conclusions are done on the day
practice coming up with essay plans with past hsc questions (check out tutor tales) so you can see how "adaptable" your essays and points are
if you can't remember big chunks of information, reduce all your sentences to dot points so like "quote - general effect, key words from the sentence" and it should flow together if you run through it enough times