How to be quick ?

You should pre-set and pre-focus your camera.

This is fairly easy with 35 mm lens; this is also a reason why 35 mm lens was considered by many photographers as a primary lens for street shooting. Also this focal length doesn't isolate the subject from his surroundings like longer lenses: the depth of field is remarkable and even areas out of focus are reasonably sharp.

Use a good, proved 400 ASA negative film. This speed gives you opportunity to use small diaphragm sizes, giving you great depth of field and permits using relatively fast shutter speed. Because you are using negative film, you can be couple of stops off correct exposure and still have printable negatives.

Set your lens at f/8 and 4 meters (12 feet). With 35 mm lens you will be able to capture all from 2 meters to infinity. For closer ranges you will need to change distance setting anyway, but you will be ready for most situations you will encounter.

Set lens at f/8, exposure according to modified sunny-16 rule: at 400 ASA set shutter at:
1/1000 when sun is up
1/500 when at morning or afternoon
1/250 when no sun or in shade
1/125 when no sun & shade
1/60 when before the storm
1/30 when in bus, shop or tram

Wind camera before you go shooting and wind IMMEDIATELY after you shoot. Don't use autofocus; using it requires lot of thinking and knowledge when you want to actually make photos. Also it takes some time for autofocus to set the lens. And this awful noise!!! :-)

Smile and nod to people you are photographing. Never ever act suspicious-ly, don't be afraid of shooting unknown persons. If they like it, they will smile. If not, they will say you so.

Uhh, stop this writing/reading and go shooting !!! Now!!!