Double Negative wrote:
Street isn't really my forté either, but I've been shooting more and more of it. Your confidence builds with time!
My experience was that I came to the point where I wanted to do street photography more than I wanted to be nervous about doing it. I sort of made myself work through the jitters and before long, I was no longer afraid of people's reactions. As Garry Winogrand said,
"I want to make pictures, not friends." I can see his point - I already have friends. It's photographs that I want.
I have had a few conversations with people about why I took their pictures or about what I'm doing, about what street photography is, etc. I am upfront and do not get defensive or nervous and simply explain what I'm doing and why. I have never been yelled at, threatened, chased, had someone try to coerce me into giving them my film, etc.
It doesn't hurt to carry a small album of 4x6 inch prints in your camera bag to show people your street photography if they ask questions. I also carry a few of my 6x8 inch postcards with my contact information and website address with one of my images on the card.
These little things will establish you in their minds as a serious and legitimate photographer and not some shady type who lurks in the shadows and photographs people for nefarious puropses.