1. Alternate placing books horizontally and vertically.
2. Use framed pictures as bookends.
3. Put sculptural items, framed pictures, or small framed art on top of horizontal stacks of books and layer photos behind.
4. Pick one tone (as shown in the 2nd pic) for a clean look.
5. Lean plates and/or artwork along the backs of the shelves to anchor them.
6. Use baskets and boxes for storage and to add texture. Offset with smooth curvy vases or urns.
7. Be sure to step back often as you arrange to assess your work and make adjustments.