In this video I talk a lot about how nonfiction authors should be focusing on courses or other digital products to increase revenue from their list, but you don't HAVE to do any of that. Still, there are some valuable tips on breaking up your book into lots of pieces of content, not only to boost organic traffic, but also to discover your most popular subjects and what appeals to readers (which will help with your positioning and branding).
Don't hide all your content behind a paywall and focus on sales... give away a lot of value and offer incentives to buy the book (an extra guide or PDF). Then, depending on your field, upsell them something - even if it isn't YOUR course, you can probably make a list of useful resources that people interested in your subject might like. Find some products you recommend, even basic stuff like web hosting, and build a long, specific tutorial helping them to overcome one common pain point; you can earn some extra money from the affiliate sales.
For example, I have books on book marketing - but one of the biggest pain points for authors is setting up a website and email list. So I made this course; I'll make a huge, free article after I finish this course and share it with everybody on my list. At the bottom of that article, I can plug my book marketing books, my email course or earn some money by recommending email list building tools. The more helpful that article is, the more people will share and link to it, and the more people will buy my nonfiction books (because, most people won't be ready to take action, buy tools or sign up for a course - but a $2.99 book might be attractive to them at that point).