Marissa Mayer (Google Head of Locations, formerly Products) touched on this problem in a talk she gave. I vaguely remember, but I believe she talked about how a

Marissa Mayer (Google Head of Locations, formerly Products) touched on this problem in a talk she gave. I vaguely remember, but I believe she talked about how a painter was always overwhelmed by his blank white canvas so he would paint a small stroke on each canvas to start with that. Often times having a start point can help spur you into motion. One way I like to get started with design is by working on the logo first (which is relatively simple, since its plain text at first), and then continue to build around it until I'm past the block. Hope that helped.