I would say don't have super high expectations/put too much pressure on yourself to do well. Personally, I had a good SAC average for my 3/4 subject, methods, but burnt myself out getting incredibly stressed over the exam and did way too many practice exams. As a result, I became incredibly sick and nearly had to be hospitalized around the exam period, but showed up and did my exams anyway. My sacs ended up scaling from a 92/A+ down to a B+, and I ended up with a 36 which was miles away from my goal of a 42. My advice would be to make sure the subject you accelerate is one you are passionate about, and don't put yourself under extreme pressure to do well in it. For example, I really chose the wrong subject to do early as whilst I am decent at maths I don't love it, whereas I do love my other 5 subjects which I am doing this year in year 12 and am far more consistent across the board in these subjects.
