I'm often asked what settings do I use to make sure not to miss the decisive moments in street photography so here is a brief overview. The most important thing is to have flexible settings that allow you to set and forget about them. The last thing you want is to stumble through buttons when you need to focus on the composition.
ISO - always set to auto. I basically haven't used that dial for a year. By setting aperture and shutter speed manually and then adjusting the exposure compensation, I make sure it's as low as possible. It's also set to max value of 6400 so not to go too high in low light situations.
Different light conditions
On a bright, sunny day aperture is between f/5.6 and f/8 which implies shutter speed has to be between 1/500 and 1/1000. Rarely I will go to f/11 when practicing zone focusing method. If I'm going for hard contrast and exposing for the highlights, I will set exposure compensation to -2 stops or even further. On average it's set to -2/3 of a stop to preserve details in the highlights. On an overcast day I'll prioritize shutter speed, so I'll set aperture as low as possible (f/2 - f/2.8) and keep SS at 1/500. I would rather risk missing the focus than having an unintentional motion blur in a photo. And lastly at night my go to setting is f/2 - 1/125. It's the best compromise between high ISO and motion blur. At least for my lens.
Focus is in most cases set to continuous auto focus, meaning it locks down on the subject and then I do quick adjustments or wait until they are perfectly positioned in the frame. I use manual focus if I'm doing zone focusing (having a zone range where everything is in focus, with wide aperture) which is rare, or if I'm pre-focusing on a certain spot.
That's it. Like I said, I like set this and forget about it until the shooting conditions change. Let me know if you have any questions.
Some example images.