For some context I've ranged about 80's all year with hard SACs and am ranking 1 in my cohort – my number one tip would be to just keep writing practice papers and see where your discussions/explanations are lacking through teacher feedback and through examination reports.
To get the information to stick, complete questions open book and try to ensure your responses are as cohesive as they can be with the question at hand. While you have your notes, utilising them to answer the specific question is definitely different then just copying the info down over and over again, so hopefully when you keep answering open book questions you'll get a sense for how to best use the information and thus you'll consolidate your information rather than just memorising it. Closed book answers will also help you locate where in the study design your memory is lacking, so I'd suggest to go back and forth between methods to both test and build your memory.
It seems like our schools are similar– the teachers will be extremely harsh in marking to ensure that your responses are "in line" with what is roughly expected on the exam, which is at a detriment to your SAC marks. If you've passed all year, don't fret, because usually the exam style questions will be relatively more simple and your marks will have a chance to even out. With getting exams marked over, definitely see if you can reach out to your teacher or even another legal studies teacher at your school, as they have the best expertise and will most likely emulate the holistic approach seen by examiners, especially with the longer answer questions, that we can't do simply with the exam report.
Make sure when integrating your evidence into your answers, whether you're talking about a specific case or using Section B material, that you do so early on and use the evidence to build off your explanation rather than chucking it on at the end. This is some advice my teacher has given me and I didn't even notice I was half-heartedly using evidence until after the last SAC– so definitely useful to be mindful of how you utilise your evidence.
Don't be afraid to just keep writing– definitely with the time constraints of an exam or SAC this can be difficult, but when a question is worth a lot of marks, try to put down more points then you think you should (and don't be afraid to go over into the extra writing space). Not saying you should bullshit in your answers, but adding a few extra explanations to your points won't hurt your mark, especially when marked holistically.
Lastly try to incorporate your English writing style into your longer style responses. This might look like having an introduction, points and a brief conclusion to ensure you are addressing everything adequately and in a format that is easy for the examiners to understand. Signposting language is also a must!! (Although, however, this is due to, thus, e.t.c) This just helps your "essay" flow and your ideas get across better. It's definitely difficult to start off with, but even just the use of conjunctions (whereas/however/e.t.c) and breaking your points into paragraphs will help you structure your analysis better and thus get you more marks.
I hope this advice helps and isn't too convoluted– you can PM me if you want me to explain anything else! Good luck on the exam (: