Here's a great photo from dlemieux's Flickr stream. She has several great sets of street photography. One way to get a great photo is to scout out your location looking for a good background. Then setup and wait for people to walk by. It's the people in front, framed by the background that can give you a great photo.

Here's good example of this technique from Pensiero's Flick stream. This great orange wall is brought to life by the subject walking by. One decision you'll have to make, should the subject be walking into the frame, out of the frame or sitting still in the frame?

Here are two more examples from Pensiero's Flick stream. Notice how the rule of thirds is used to balance the image. Think as well about light, shadow and pattern when you are looking for your shooting location. Don't be afraid to ask someone to walk by several times if you miss the first shot. Most people will be happy to help you out.