In my experience, one of the most difficult design challenges is styling bookshelves. The funny thing is, most people have bookshelves in their home, but very few are happy with how they look. When I style bookshelves, I keep in mind three things: 1) the color palette of the room 2) place photos in similar frames 3) objects tell a story.
These simple shelves flagging the fireplace and large television needed some cohesiveness and de-cluttering. I selected books that were similar in color; thus bringing out the blue/green furnishings. Adding white (or black) as a grounding color works to pull the look together. I like to add a bit of organic elements such as the moss balls and fig leaves. Fun pots and vessels balance to the arrangement.