Rule Number 1: Walk. A lot. If you drive, don't. (Unless you've seen Lee Friedlander's book "America By Car").
Rule Number 2: Pay Attention! (This really is Rule Number 1).
Rule Number 3: When you see a bathroom, use it. (To paraphrase the master of street photography, Garry Winogrand, no pictures happen while you're in the bathroom, so don't worry that you'll miss something).
Rule Number 4: Be In The Moment. Each day starts with a blank canvas (or in today's parlance, an empty memory card). Forget about yesterday, don't concern yourself with tomorrow. (Although photography is fascinating in that it deals with all three at the same time: a moment from the past, looked at in the present, preserved for the future).
Rule Number 5: Be prepared. Know your song well before you start singing. (Just had to use that Dylan lyric. The point is, know your equipment, take advantage of what it can do, and carry a spare battery. But being prepared also means to be aware of, to be inspired by, and to build on the greatest traditions of literature, painting, dance, music, photography, and more).
Rule Number 6: Pray--occasionally--to the photo gods. (They often seem happy to oblige us, particularly when the previous five rules have been observed).
Rule Number 7: Follow your intuition. Anticipate. Expect The Unexpected. (These are really three different rules of street photography but they all go together. Because seriously, you just never know when a boy will fall over a wall as a soldier marches by).
Rule Number 8: Patience is Paramount. It may or may not be virtuous, but patience sure comes in handy. A sort of famous photo wag once told me that Cartier-Bresson once told him that he (Bresson) had made 50 worthwhile photos in his life. Considering that his (most amazing) career lasted decades, Bresson obviously spent a lot of time waiting for those 50 Decisive Moments. With patience, I presume.
Rule Number 9: Remember what Diane Arbus said--"I really believe there are things nobody would see if I didn't photograph them." (To that I would humbly add this: look for special transformative moments unseen by others but recognized by you, the photographer. You know, those fleeting split seconds that reveal life's magic).
Rule Number 10: Have FUN! Be JOYOUS! Dance to the rhythms of LIFE! Soak in the THEATER of the STREETS! (These are the most important rules of all. Speaking of which, if you'd like to learn more about street photography, please come to my Seek Workshop, "The Theater of the Street", June 6-10, in beautiful San Miguel de Allende, Mexico.