Hi! I completed Psychology 3/4 last year so hopefully I can help out.
The content between 1/2 and 3/4 is honestly different and the topics don't exactly overlap (except for research methods of course). Therefore, I feel like it would be hard to determine how well you might go next year as it always depends on your strengths in the subject. You might like the content in 3/4 better (and yes it is way better)
Being at the top of your cohort does help, however it does not guarantee for you to get a 50 (the exam does). As schools can make the SACs easier/harder if they want their cohort to seem stronger and hence gain higher study scores, VCAA scales your SAC scores higher or lower depending on how you did on the exam. For example, if Person A was ranked 7th in the cohort but gets a 95% on the exam, while Person B is ranked 1st in the cohort but gets an 85%, their study scores will be different. Therefore, it is not that important if you are not rank one, but of course try hard for your SACs and especially your exam 🙂
However, in terms of maintaining your rank, what I would recommend is really understanding the content. Lots of people had cue cards, which helped them remember content along the way, but I personally found this time consuming. During SAC times, do practice SACs and get feedback every time rather than marking it yourself as you will always be biased (hopefully your teacher will do this). Practicing questions is your number one way of getting your desired study score. This applies to the end of year with exams (quality>quantity for amount of exams)
Link concepts to your surroundings or make stories (e.g., linking spinal reflex with the time you burnt yourself while cooking, or remembering the stages of the transtheoretical model by remembering PC-PAM relapsed). This may not apply to everyone but personally since I am a visual learner, I often drew little drawings in my book that linked to concepts so whenever I was in the exam, I would remember that exact drawing.
What my teacher did was encourage us to get into study groups with people that we weren't necessarily "friends" with, so that you can constantly motivate each other and keep each other accountable. Honestly I believe that was what really boosted my exam score in the end as well.
Altogether, just remember to relax during year 12 as well. It is a very stressful year and nothing is ever guaranteed and your mental health matters more! Your SAC scores do not indicate what exam score you will get, even if constantly being on the study score calculator is tempting. You've got this!! 🙂
(...hopefully that helped 😅 )