Your designs are really elegant, and well crafted. Often times you see abstract objects that were obvious results of traditional modeling failures or mistakes, and it's really easy to just call it "abstract". However, your works are obviously well-crafted with good topology and direction. I like your color choices and materials as well.
you need a camera and the proper render settings. anyway, the DOF on this picture wasnt made by the physical render, that's a post work in Photoshop. I was playing around a lot with DOF but i find it more usefull if i make some kind of DOF or blur as a postwork in photoshop, its more comforatble to me that way.