Often a good technique with street photography is to choose the static part of the photograph first and wait for someone or something to walk into the frame. For example in the image above I already knew that I wanted to photograph the lighting of the butter lamps. This was very early morning in a temple in Patan in the Kathmandu Valley.
I perched myself just next to the lamps, which were happily burning along all by their lonesome. A few people wandered in and lit some and then moved away but they weren't quite what I wanted.
After a few minutes of waiting this lady walked up with glasses on. It wasn't something I was particularly aiming for but I noticed that the lamps were reflecting in the lenses of her glasses, providing a little bit of fill light just to that part of her face.
That was exactly what I needed as all the other glasses-less people, when they lit the lamps, had their faces in shadow. Their faces were almost a black hole in the middle of the image. With a little bit of light reflected in the glasses it gave me the perfect counterpoint to the flames in the right hand side of the photo.
I'll often use this technique. I'll just wander around looking for nice backgrounds, or interesting features, and just sit and wait until somebody interesting walks into the picture to give it a bit of special interest. A slightly longer telephoto lens is helpful in these cases so that you can be really unobtrusive when photographing. Get your zoom at exactly the right level for the picture you want to take, have your aperture and shutter speed set correctly and just sit and wait. It's almost like big game hunting only you're looking for pictures!