Take some time off of work and go somewhere. Spend many, many hours driving in remote and unfamiliar places. Go and explore the world. Without the distractions of work it is amazing how your mind can wander and dream up ideas. I included one of my favorite pictures from our trip of Monument Valley using a long exposure shot with a car's tail lights creating trails. The second photo is an example of how the rotation of the earth creates trails when taking even short (30 second) "long exposure" pictures of the stars. This was taken at F1.8 at 50mm on a Canon T1i. You don't have to look too closely to see the star trails. You can also catch a faint glimpse of the Milky Way across the image.