One of the most frustrating aspects of street photography is that you really can't take your time with an image the way you can with conceptual photography, or portraits or landscapes or really any other branch. Your subject is a fleeting moment, one that is impossible to predict, and you often have a window of less than a second in which to get the settings right and press the shutter button. Time is of the essence, so efficiency with your settings is a must.
A common misconception with street photography, more so than with other types of photography, is that a DSLR camera is necessary. In fact, many photographers (the author included) prefer point & shoots, albeit high end point & shoots that have the same full range of manual options as a DSLR and with no sacrifice to image quality. The main advantage of using a point & shoot in street photography is that it's inconspicuousness: people are less likely to notice it, and thus turn away or otherwise change their behavior. They slip easily in and out of a pocket, leading to seamless movement that precious few people even notice.
Having presets is of critical importance so that you don't have to redo your settings every single time. That doesn't mean go into automatic: just having an idea of what you will need and the sort of images you want to capture can cut down on your time considerably.
Depending on your style, it might be better to stay in a lower f-stop, a shallower depth of field. Street scenes often have very busy backgrounds, making it difficult for the desired subject of your composition to stand out.
Fast exposures are also your friend: people move, and when they move, they often move quickly, creating undesired blurs that may destroy what you were trying to capture in their expression. Street photography can thus be very difficult at night, when a longer exposure is often necessary. It may be worth it to move to a higher, grainier ISO in favor of shorter shutter speeds.
Automatic focus can be your friend if the manual focus is cumbersome to use, or even if it isn't. Many digital cameras are equipped with fantastic automatic focus software that really can get it right where you need it to be, and fast.
It's better to shoot big, meaning to include more in the framing of your image than you might necessarily need. This gives you a maximum of editing ability later with cropping, say for instance if your subject suddenly changed pace, or if you noticed something in the frame afterwards that you wanted to be the focus of the picture instead. It can only give you added flexibility. Also, it's less time spent zooming in and out, giving you more potential time to either perfect the current image or to take more pictures.
This might all sound a little overwhelming, but the more you practice, the faster and more efficient you get. Familiarity with the technical aspects of your camera and the speed at which you can get exactly the settings you want can only help in the ever-fluctuating world of street photography.