When we moved into this house back in August I fell in love with our huge built-ins in our entry hall. It definitely took some time to fill them in the way I wanted though. My method was to put every thing up on the shelves first and then rearrange until I settled on this:
I’ll probably rearrange again in a couple months, but for now it works. The bottom shelf is empty, but I intend to put some baskets down there eventually.
I worked within one shelf at a time, and spread out the frames, tchochtkes, and rows of books so that it looks somewhat balanced. We wanted our books to be separated according to classics, non-fiction, fiction, religious/spiritual, reference, etc. So that helped too in deciding where everything should go.
I have a whole Pinterest board dedicated to bookshelves and built-ins (here) for inspiration. Check it out!