We have a lot of books, some in the units and more in the hallway. People love it and sometimes mention that it’s what drew them to our listing. I grew up in a house with walls and walls of books (and LPs) and it never felt cluttered, so I have very strong opinions about books and how they are displayed, so consider all of this “IMO” ahead of time. If done correctly, they add texture and visual interest and not clutter.
For easy cleaning and to be gentle on the eyes, organization-wise, I recommend that a shelf has either all books or no books. If you do half a shelf of books and then a knick-knack next to them, that will be harder to clean and it makes both of them feel like clutter. And the whole room will feel subtly uncomfortable if there is even a single teetering bookend 
Make sure that the books are all aligned at the very very front of the shelf (regardless of your personal preference), they will look tidier this way because different sizes (depth not height) of books will look more uniform and they sort of become part of the furniture or the architecture this way - and you won’t need to dust an inch or 6 inches or whatever of the shelf in front of them all of the time.
As far as how many shelves of books, generally, the more the merrier, but you do want a few shelves without, to create dimension. Sometimes it’s nice to have some large coffee-table-books displayed singly or in a set of 3 and they are the only type of book, along with atlases, that should ever be horizontal. I agree with @NordlingHouse that it is nice, as a guest, to have a shelf or two that is available for my use. But rather than completely empty, I put something like a pretty tray or a nice bowl. Because even better than a shelf for your stuff is a shelf with a way to organize your stuff, as you would have at home.
It feels better to take your watch off at night and put it in a hand-carved wood bowl rather than set it down loose on a shelf. I also put a tiny bowl or pretty china tea saucer next to the bed for jewelry. People will leave a lot fewer earrings if you provide something to stash them in. But be warned, they will also use that dish for disposable contact lenses, but it’s better looking for them on the floor. Though this seems like a detour from books it really isn’t. Shelves that don’t have books are best decorated with useful objects like trays and bowls (attractive ones of course).
The proportion of shelves with books and shelves without books will depend on the use of the room and the other stuff in it, it should feel balanced somehow. Get a good soft bristle attachment for your vacuum to dust to the tops of the books.
Though I do organize my own books by the Dewey Decimal system 
, for an Airbnb, I think it’s more practical and a lot of extra fun to have no organization by subject or type at all. It promotes discovery and exploration, which is the very best part of looking at a book collection that is not your own. And in a practical sense, you never have to wonder where a book goes, you only have to fill a shelf, there will be a lot less stress for both you and guests. If the books look too organized, there will be hesitancy to touch them. Also, if you’re worried about the types of books you have, not organizing by subject will blend them.
You can always get some used books that are subjects that you don’t already have to mix into yours, for fun. I bought more or less random books, both new and used for our Airbnbs, strategically creating diversity and I’m always surprised at which books seem popular with different guests. If there are enough different types of books people are less likely to get caught up in getting offended by one of them. If you don’t like the Famous Serial Killers book, then you can just grab Golf Courses of the World and move on 
If your listing has a full kitchen, don’t forget to add some cookbooks.
Never ever organize books by height or, god forbid, color. Magazines (which I adore) don’t belong on bookshelves unless they are special enough to be in a clear-top archival box, get a cute basket or better, a magazine rack.
And for the record, if a guest didn’t like having books for some reason, I don’t care, they can just get the hell out.
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I’ll have to fortify myself to the loss ahead of time…
