The best advice I ever got

From tech (Larry Page) to Wall Street (Peter G. Peterson) to the military (David Petraeus) to entertainment (Tina Fey), accomplished people tell Fortune about the advice that most influenced their lives.

Mayor of New York City, founder of Bloomberg LP

I can't remember who told me this, but I certainly didn't grow up knowing it, so I must have gotten this advice at Salomon Brothers in the 1970s. The advice was, first, always ask for the order, and second, when the customer says yes, stop talking. I have watched more people make great presentations, whether they're trying to sell to their family or in business or in government, and never get to the point of what they're trying to get out of it. And too many times when the customer says yes, the person who got that answer just doesn't stop talking. Worst advice? The worst advice that people can take is to react before they've had a chance to think. I think we all say things and wish we hadn't said them. Ready, shoot, aim is not the smartest policy.

NEXT: Larry Page