You can build an entire world beginning with a single image. Today, look at Dave K’s Beach Sunset. (If the photo is no longer available at that URL when you click through, use the alternate description at the end of this entry.) Spend a few minutes just looking at the photograph, taking in every detail–coloration, textures, topography. Then sit back, close your eyes, and imagine that you’re zooming outward until you can see some of the surrounding area. Look around, noting everything you see–animals, colors, people, structures. What changes and what stays the same?
Open your eyes and free-write for at least ten minutes or one side of a sheet of paper. If you like what you have so far and want to do more, sit back, close your eyes, and pan around to one side or another in your mind’s eye until you see something new and interesting–a change in the landscape. Again, open your eyes and start free-writing.
Finally, take a new sheet of paper and write down a list of details or rules that seem to hold true for this world that’s taking shape before you. This could be as meta (and broad) as genre or as specific as details of the society of people living on this world–if any.
Alternate description: Sunset casts a golden glow over a beach. Water has eroded the sand and stone away in layers, leaving behind broad step-like formations. Hills or mountains rise up across the water, silhouetted against the softly-lit sky. The water appears calm, disturbed only by the barest ripple of breeze.