There's no rule that says that artwork must be two-dimensional. I love the way these objets are elevated to masterpiece status by the use of frames. It's fun and feels young, but the neat organization of the frames adds sophistication.
The easiest way to make eclectic pieces work in the same space is to make them more uniform with one another. This is done here by using the same frame for every piece and by hanging the pieces in an evenly spaced symmetrical format. If you're not someone who pulls off an eclectic look easily then this is a good route to go to create a polished appearance for your display.
This is great & inexpensive! I would put the individual items on shelves within the frames if you still want to use them. Great for kids & teens rooms to keep their "stuff" organized! JR Nuerge Eco-friendly+Eco-nomical=Eco-fabulous! http://www.jrnuerge.com