I'll freely admit that I don't study the rule book as much as I should, especially this offseason (was laid off, got hired somewhere else, etc.) but here's what works for me. I've accumulated a bunch (I mean, a LOT) of NCAA quizzes, probably half have answers, from different sources, and I'll take 10 or so and work through those, and as part of the answer, identify the specific rule(s) that are involved. So, that gets me into the rule book, but with purpose.
Personally, I've never been able to learn by 'just reading' the rule book; that's just not how I learn. I learn best in a hands-on or visual way, so that's what works for me. I cringe whenever I hear new officials be told 'Just go read the rule book, it's all there.' I don't think any successful educator, ever, has said 'Here's a geometry or algebra book, just read it, and there's a test at the end of the semester, good luck' and have the student be successful.
It annoys me to no end that the rule book ARs are not immediately following each associated rule. I'm going to try to fix that when the new book comes out and see if I can edit the PDF to move them around. It's a huge PITA to have to constantly flip (real book and PDF) from one rule to AR back to another rule etc.
The other thing that I have found super helpful, is taking rules, and trying to create study materials that others could use. That 1) gets me in the rule book, 2) helps me find a way to communicate/explain the rule effectively, and has practicality. Sometimes it's PowerPoint, sometimes a Word doc, sometimes an Excel sheet, sometimes just a 'cheat sheet' type summary, but doing that really helps me. It also is very useful for learning correct mechanics. I have no idea of the exact number but there's a fair amount of officials who work 4 and 5-man 11-man as well as 4 and 5-man 6-man games, and sometimes 7-man crews, and often multiple positions within each of those, and it can be just as challenging to remember correct mechanics, as it is for rules. And in my experience, correct mechanics lag far, far behind correct rule interpretations, in what officials know.
As an example, this is something I created last year to serve as a cheat sheet of sorts to review for crew responsibilities for new officials. As always, if I got something incorrect (which is likely) please let me know. And if it's useful for you, great, and please share it with others.