Well, i'm kinda doing my HSC this year
but we had a state ranking Ancient/Modern/Ext History student from our school + all our Ancient teachers are HSC markers, so these are a couple tips i was given by them
1. Basically try and get the most marks in the personalities and time periods sections. Those are the places where people score the worst, if you can show you are average in the first two, and a lot better than the average in the last two, then you are at a great advantage with scaling and such. For example: the state average in Pompeii is 19/25; Historical place (ie Sparta) is about 19/25 as well state wide. For Historical time periods (ie Fall of the Roman Empire, Julio Claudians, etc etc) the state average is 11/25 - which is a big drop.
My teacher suggested strongly that you start the paper from the last to first section, and try to aim for about 22/25 average in each one. (strong band 6 mark)
2. Use historical references and terms specific to the topics you are learning. Ie for the Julio Claudians a specific historical term would be princeps, pro consul, res Republica, etc. These terms suggest to the marker you know the topic in specific detail rather than just bluffing your way through on general knowledge
3. Don't bluff/ be precise and straight forward. Don't think it's like an English essay where flowery words work in your favour. Historian essays must be essentially just facts linked to historians, with the paragraphs closing on your personal interpretation of these sources, and how you link it to the question. Simplistic language is better in Ancient History.
4. Make sure you are comfortable at answering any of the syllabus dot points as a 15-25 mark question. Try to merge concepts from the dot points to cover a large range of topics so you don't have to remember so much. Also limit the amount of historians you use. Aim for 2 Ancient and 1-2 modern historians to ensure you cover a range of perspectives, without having to learn a range of names.
5. Practise papers. Yeah, these are the best way to see how much you remember.
good luck
