The main elements needed to utilize in becoming a successful street photographer would be knowledge of the subjects, awareness of the environment, a focal theme that can relate to society as they are the audience and a positive attitude

Full knowledge and control of depth of field. And an eye for perspective and point of view. Being mindful of composition. A photographer isn’t just a picture taker; he or she is an artist!

You can learn a lot by looking at preceding photographers. In this case check out stuff by Henri Cartier-Bresson -After Minor White, my favorite post WWII photographer.