Street photography is a fun challenge. One trick is to not look like you are taking a picture. Henri Cartier-Bresson used a 35mm rangefinder camera. He set the focus at infinity and set the aperture and shutter speed so he would be in focus and sharp. He would shoot with out looking through the viewfinder. Just holding the camera at chest height with a very quiet shutter. With today's digital camera, you can do the same but set the camera on continuous so you have a better chance of catching the decisive moment.