Based on this information, your current performance seems consistent with an ATAR of up to 78.@jimmysmith560 Would love to call in the big guns if you don't mind
Modern History is your best-performing subject, especially given your optimal rank. Should you also achieve the highest HSC exam mark within your cohort for this subject, the moderation process will essentially work in your favour, meaning that your overall HSC mark would be made equal to your HSC exam mark. This gives you a great opportunity to maximise your result in this subject, and consequently maximise its contribution to your ATAR. Hopefully you did well!
Your performance is not unfavourable in English Advanced, Geography or Legal Studies, although there is clear room for improvement to your overall performance in each subject, which is possible through favourable HSC exam performance. Hopefully you did well in your English Advanced HSC exam, and best of luck with Legal Studies and Geography. You also still have plenty of time to continue preparing for the latter, and you should definitely make the most of it to ensure the best possible result.
On the other hand, Mathematics Standard is your lowest-performing subject and will likely prevent you from reaching a higher ATAR at this stage. Improvement is therefore crucial to reduce the chances of this happening, so hopefully you did well in this subject's HSC exam.
I hope this helps!