I made a checklist a couple of weeks ago to target specific areas. For example: Inequality proofs, Direct proofs, Divisibility induction, Difficult projectile motion, SH, tough vector proofs, 3D shape proofs eg. Tetrahedrons , Recursive induction, Complex number geometric proofs. I found Cambridge enrichment to be useful to an extent; its just, some of them are far too difficult for them to put into the HSC so I think there's better ways to use our limited time. I'd say focus on Steve Howard Mathematics and make sure you're really strong at proving things. Otherwise, SmarterMaths can be a really useful resource if your school has it. If not, I'm happy to upload some of the SmarterMaths topics.
If you feel like you're running out of time, just open up an ext 2 textbook and put a number between 1 and 5 next to all the topics, then prioritise based on what needs the most time, and work your way up.
The two attached documents were useful.