I am still not very comfortable at this street photography thing.
I hear and read conflicting ideas about asking permission, or not; about using a discrete camera or bringing out the bazooka; about legal, moral and ethical issues; about model releases and personal brand. I'm not surprised that many other photographers find street photography difficult as well.
Imagine if you could walk through an urban landscape in 'bullet time'. Imagine walking through a frozen-in-time world and being able to compose and photograph the images that you see unencumbered.
I'm not sure I have enough experience yet to offer any advice but for now my strategy is to use a big lens, keep moving and look completely disinterested in the images I capture. Oh, and to smile politely when I'm sneered at!
Photo: Robert Rath, '366 Days of 2012, Day 238 - A Private Moment'. 1/100s f/2.8 ISO-3200 200mm