First, congratulations and well done, David! It looks really good. (it's not the kind of content I like, but I was "getting" the spreads instantly, which is a really good sign).
David seems to have really hit all the marks well, this is truly how you're supposed to go about it (although I don't do it that way!) but I will make one substantive remark, which many of the Major Names in giving advice don't seem to give very often:
Make lots of books. Make little ones. Make big ones. Make books to test ideas.
THEN make your big book.
You can use Blurb to make very cheap test books (as low as $2.50, I think). You can just get a saddle stapler and make some pamphlet style books. You can learn to sew a binding. You can glue photos into notebooks. Make lots of little books, stupid books, books that don't matter. Learn how to make books with easy projects that don't matter much. Your magnum opus is going to be hard enough without having to learn everything about books at the same time.
While you're at it, take some books apart. Just get an xacto knife and start cutting. Your local library may have a "free books" rack containing stuff they're getting rid of that's so terrible it won't sell. Pillage it and start ripping, tearing, cutting.
But also, so all that stuff David did as well. Tearing a book apart will teach you nothing about publishers, or selling books, or how offset printing works, etc.
Everyone seems to jump in with their Big Book first, and they wind up trying to boil the ocean.
Props to David for making it through, he hints at, but I suspect is shy about revealing just HOW MUCH WORK it was.