Palms Sweaty Mom's Spaghetti
This about only getting one shot do not miss your opportunity (assuming you picked up on the Eminem reference)
*TIP: if you see something you want to take a picture of, take it right then and there. Don't tell yourself you'll take it on the walk back. Or that you're there for 5 more days you have plenty of time. Or hesitate taking the photo because you don't want to draw attention. I've learned this lesson the hard way too many times. I've seen things that I thought "wow, that would be a great shot." And then I've either hesitated and the moment has passed. Or the week flew by, I forgot, and I never went back to the take the pic of whatever it was. The weather could change and therefore change the photo. Prime example, walking through East London. Pass a Holiday Inn. Which in the hip, artsy Shoreditch borough of London, that was very NOT hip and outdated looking. Outside the main door were two identical twin women. Probably in their early 50's, 5'0", wearing black puffer coats smoking cigarettes in perfect synchronization. A living mirror. Holy shit. That is cool I should take a picture. Nah, then I have to get my camera out...they're gonna say no...eh fuck it.
Walk up to them. Hi. They turned out to be Russian. Pretty sure. Didn't speak much english. Asked them if I could take their photo. one said "ok!" the other one just continued to smoke and kind of gave this look like "eh, this is weird why does she want our picture but whatever." The wind kicked up blowing one of their bangs and instantly making them look less similar. One put her cigarette down and did a no-teeth smile instead. The magic moment was gone. But it's ok. Photos aren't supposed to be perfect. To me they aren't anyway.
When it comes to shooting street portraits my rule is: it's easier to ask for forgiveness than permission. When you approach and ask to take their photo it can often disrupt the mood they were in or what they were doing. It can disturb the peace. Other times they can actually perk up and pose for the photo. Which is fine, too. Rarely, has anyone ever been upset I took their photo. Can't really even recall that happening. I don't apply this rule to children though. I would always ask their parent's permission.
Moral of the story. See it. Shoot it.