I go to girraween high and like our extn test was like daym easy, possible to get 100% most top students getting in the high 90's...and for extn i havent gotten a mark below 80 this year. Post some of these really hard questions that your getting. Are yous having problems with some of the yr 12 topics or something that your doing in advanced?
As for the independant study, I suppose i use tutoring in that sense and then just act like a parrot and repeat everything in class to test my knowledge when we go through the topics. I agree with the whole tips things because really maths is a subject that if you have questions with insane working out, you can pretty much grasp any concept. Writing notes, not copying them from the textbook, explaining how to do particular questions may help. Helped me especially with t method for trig where I was totally lost at first and then ended up doing extn questions from cambridge with ease!