I'm haven't done spesh but doing methods this year.
I haven't really made a bound reference as I've never really used it but I've been feeling quite guilty as exams are approaching and teachers are insisting that need to make good bound references. (lol)
I don't even know how to start... However what I'm planning to do is put questions I have difficulty or concepts I am still rusty on. My advice. Don't waste time thinking about what to put in your bound reference. Sometimes you feel somewhat not confident with a question but as soon as you see it, you automatically remember what to do and can kinda work your way to get the answer. You have been getting good sac marks (good indicator that you are competent in the course), just dive into practise exams. Then correct your exams, note your mistakes. And if it was a question you did not know how to do, or struggled with, put it in your bound reference. (If the same mistakes keep coming up, its a good idea to take time to add extra examples etc.)
Making bound reference when doing practise exams is the perfect time to start (if you havent bothered earlier in the year). It's best if you add to it over a long period of time with things you are constantly having trouble with . No point add things you are already confident in. Then it's good to regularly take a look at it.
Treat your bound reference as a form of revision, not something you will likely need to rely on in the exam.