Hey buddy,
I achieved a band 6s in 3 low scaling subjects identical/ similar to yours: Modern History, SOR1 and Gen maths 2.
Here's a few little tips regarding things I did that worked:
For your history, make sure you have a comprehensive set of notes completed well in advance of tests/exams (10/10 would reccomend purchasing the Ken Webb books for your topics if you don't have them - AMAZING.He includes historiography as well) I'd break these notes down too, and know your condensed version back to front. Mind maps by syllabus dot points are awesome to help you remember. Past papers are also superrrrr important as you get to the pointy end of the year, but I'd look for relevant questions throughout the year. I would suggest doing some in their entirety, but you don't have to do all. Sometimes its just handy to plan or dot point essays or other short answer / source questions. Make sure you have heaps of quotes from historians (historiography) too - I hear its more important than in modern.
For SOR, I scored a high band 6 in trials and the HSC using the sor excel book as the basis of my notes, and adding a few bits and pieces from past paper answers, scriptural references and a few other bits and pieces from class notes. Practice is essential, as questions are often similar, so its reaaaaally important you do past papers. Also, break down topics into just a set of dot points; I.e. For your significant person, just dot point their main contributions/impacts and make sure you know these. This'll ensure you remember the main things they did, and if you put enough effort and time into your main notes you'll find it easy to elaborate on them.
For Gen maths 2, practice is without a doubt the key. Keep up with class work. Go home and do any questions from the exercises you did that day, even if they're ones you weren't told to do (e.g your teacher tells you to do all of the even number questions - do the odd too.) Ask for help when you need it. Do past papers. There's an excel workbook that goes by topic - super handy, as well as the past paper one. Knowing the content/formulas etc is also important - make sure you have notes for gen maths. You would be surprised how many people don't! They make things so much easier and good notes will give you an edge.
Not sure how coherent this is as I'm in a rush. Message me if you need anything else, I'm willing to lend a hand. Merry Christmas and good luck. Don't stress.