The image above shows a brush similar to the one I used to model my clay grip. 

Initially, I wasn't sure how to approach the grip issue. I knew I wanted to make it wider, but I wasn't sure if I wanted small indentations for my fingers or some other form of grip. Since the primary function for this hairbrush involves rotation, I wanted to design a grip that would feature a way for my fingers to grip correctly all the way around the circumference of the handle, not just one face of the brush.