Practice, practice, practice!
And ask questions from teachers, even if you feel you understand what's being taught, to consolidate your knowledge.
Learn from your mistakes; when you get a test back make sure you spend most of your time trying to analyse these and rectify them by doing them again. Don't be like those idiots who spend their entire time comparing scores nor those attention whores who are like 'fcuk i lost 1 mark bro i'm so bad now feel me...'
Simply thinking you understand what's in the book isn't good enough. In fact, in spesh particularly, I found myself making a lot of careless mistakes early on because I lacked practice. I think there's also a section of the study design which, unlike methods, mandates that students should have experience dealing with 'large numbers' or 'numbers which are challenging to manipulate and deal with' so definitely get used to that. Again, this comes with ongoing practice from working through past SACs and exams.
Alchemy and Cosine beat me to the answer

I love answering questions like this so much
Specialist isn't a fly through subject, if you wanted that further would've been the way to go... All jokes and shot's at further aside I would strongly suggest you stay with or ahead (by however much) in front of your class. It's was the first week of year 12 and I felt like my desk just went through a storm, there's paper with working out etc everywhere. It's amazing how quickly one can fall behind, struggle learning the new topics and regret choosing the subject 2 weeks into year 12 VCE.
I also suggest that you ask questions and plenty of them throughout the year. You're actually benefiting yourself and others who may not be as confident to speak up (my spesh class has 7 people so everyone wrestles to ask questions, not really but it would be a great sight to see them do it). Asking questions also allows the teacher to make assumptions towards your understanding of a subject and shows commitment to it by having a go.
Practice makes perfect. Generalizing (isn't it an s?) but true

. Don't stick to doing only chapter questions though, as my chemistry teacher says "they're the basics and help you when doing the chapter review. These in turn help you with the practice exam questions. If you don't do the basics how do you expect to do the questions that matter? Which are the exam type questions". I literally remember it word for word because he said it every time someone didn't do homework. A quote I absolutely love is: “Repetition is the mother of learning, the father of action, which makes it the architect of accomplishment.”- Zig Ziglar. A bit like free throws in basketball, no?
Do what you teachers suggest, do any extra work they tell you will benefit, ask for extra stuff if you don't get a particular topic because grinding sometimes isn't the answer

but nonetheless, use any extra resources you have because the textbook doesn't have everything!
Disclaimer: I am not a past student, I just want to help out by giving advice
I received from former students and teachers.