This photo is (I think) example of the ‘decisive moment‘ (a term with which I am not overly enamoured, but which I think applies here).
Yesterday, as I was on my way back to my office from the bank in the downtown core, I notice this slash of light emerging from between two large office towers. At about 5 feet wide, it was the perfect size to frame a passer-by. I set my X-Pro1 to f/8, 1/1000, ISO400 to expose for the lighted area, and just waited; waited for someone to enter the scene and become framed by the light. I also wanted to be sure the scene was relatively uncluttered with pedestrians.
After about 2-3 minutes of waiting, with my camera held to my eye the entire time, I noticed a scene emerging to my left. A man in a briefcase, with virtually no one around him. This would be the moment I wanted. So I half-pressed the shutter (which completely eliminates any shutter lag on the X-Pro1), and when he entered the light, I released the shutter.
As it happens, another man had just passed through the light from the right, and you can see him on the left of the photo above. While I was looking for a solitary figure in the shot, I actually think the second man in the shadows contributes nicely to the overall image, and provides nice contrast to the well-lighted man.
The lesson here is that when shooting on the street, you need to be on the lookout not just for the scenes happening right in front of you, but for the scenes that may develop over time. Look for interesting light patterns, contrast, curiosities, etc, and then work around them. Construct a photograph. Be patient.