How Should I Approach Writing an Academic Book?

I’ve started working on a research idea and now thinking seriously about writing an academic book, but I’m not fully sure how to structure it properly. Some scholars say it should be very formal and theory-heavy, while others suggest keeping it more readable for wider audiences. I don’t want to lose clarity or academic value. For experienced writers here, what would you suggest for academic writing, and how do you balance research depth with simple understanding in a book?