1) you'll need to train your eye first. this means that when ever you're out, you have to look for photo oppotunities with your eye and image how you're going to take it. To take good street photos, you mind needs to be working continually.
2) next is when you do really have your camera with you, take those shots that you've envisioned
3) take note of the photos that you missed. note down the reason, for me it is usually
a) I wasn't ready
b) didn't dare to take (usually it is because the subject will know I'm taking the photo)
c) I was walking too fast
hence identify how you miss those shots and make it a point to "practice" hence you can reduce these problems
4) learn 1 focal length. You need to train yourself to be so used to it that you can shoot without using the view finder
5) learn to be more thick skinned too
6) alot of street photo depends on chance. Hence the more you go out to shoot, the more chances you'll have.
7) use a descrete camera. A p & s and quite definately SLR is out of the question
for equipment I would recommend
a) yashica T5
b) range finder.. (anyone)
that's all that came to mind