I feel pretty strongly there's a lot to be gained by studying people who spent their life doing candid photography of their fellow human beings. I think it can help you get a feel for what did or didn't work, what's been done, and where you own taste lies. To that end, here are some resources about some photographers who in my not-so-humble opinion you should to get to know.
"Winogrand speaks of the Cuban missile crisis of 1962 as a crucial episode in his life. During the days and nights when the issue remained in doubt he walked the streets, in despair out of fear for the life of his family and himself and his city, and from his own impotence to affect the outcome. Finally it came to him that he was nothing -- powerless, insignificant, helpess -- and that knowledge, he said, liberated him. He was nothing, so he was free to lead his own life."
-- John Sarkowski on Winogrand in Figments from the Real World.
Winogrand casts a long shadow over street photography, and studying his work is an abiding interest of mine. As nearly as I can tell, photography was a kind of obsession with him, driven as he was by the idea that every scene was a photography problem to be 'solved'. Consequently, he shot a lot of film -- probably around 3-10 rolls a day, and he died with about 2,500 rolls unexposed, as well as about 300,000 images total (!) unexposed.
I probably can't do the man justice. Here are some resources to get a taste for what he's about:
- Arrivals and Departures
- The Man in the Crowd: The Uneasy Streets of Garry Winogrand
- Figments from the Real World
- Stock Photographs: The Fort Worth Fat Stock Show and Rodeo
- Coffee and Workprints: A Workshop with Garry Winogrand
- Master Class with Garry Winogrand [and Diane Arbus]
- Class Time with Garry Winogrand
- Monkeys Make the Problem More Difficult
- Interview with Bill Moyer - Parts 1 & 2.
- Visions & Images: Garry Winogrand 
- Garry Winogrand: Photographer [note: documentary in German]
The de Toqueville of American photography.