So, here's how I organized my shelves:
Top Shelf - books/poetry I love and other classics that look cool/make me feel smart (and, of course, the baby monitor)
Second Shelf - all things music ... textbooks, dictionaries, biographies, etc.
Third and Fourth Shelves - books on religion/the bible/christianity, more classics, and miscellaneous ones
Bottom Shelf - children's books (easy access for my piano students while they're waiting to have their lesson)
It's not perfect and it's not fancy, but it's better than it was. Here is the bookshelf before and after: