There's a lot that goes into successful street photography. i'll try to open up a few subjects, for your consideration
Awareness and Focus
I'm in a zone when I street shoot. I'm looking for slices of life, expressive moments, odd juxtapositions, funny scenes, interesting people. I'm totally focused on the scene, I'm part of it as I'm walking through it. Constantly watching, looking, peering, seeing. In my opinion, you cannot "street shoot" in 15 minutes. For me, it takes me a while to get "in the zone," and then once there, I hope for the best - I've said it before that we make our own luck by being there. Others have said "f/8 and be there!" -- same concept. So when I'm in the zone, I hope that I find some of the above criteria met - and I usually do, but some days I have to look harder than others. make mental note as you ply your streets... there's a shot I'd been wanting for months, but i was never near this "standpipe" when someone was sitting on it... well, patience paid off and I got it. What makes this shot for me, is the indifference of the subject (hey, i'm just sittin' here, reading my newspaper...), his reflection, and the reflection of the cab. And of course, the irony of the "sitting" on the "stand" pipe....