Per Shelly Branch, writing for the Wall Street Journal:
Bob Brown, a former Washington, D.C.-area waiter who is now a restaurant consultant in northern Virginia, has a technique he calls "By the Way." After rattling off various cocktail and entree options, he says, " 'By the way, we also have San Pellegrino or Panna.' I find it's best to mention it last, and not to offer it as an open-ended question."

Mr. Brown's script doesn't end there. "You must watch carefully. Every time a glass is half empty you should refill to two-thirds or three-quarters -- more than you would wine. The goal is of course to sell more water." To that end, he snuggles up to the person he has identified as "the lead" buyer at the table. "I say 'Would you like to have a couple more bottles chilled down?' Most of the time they say yes. It feeds their ego." [article requires subscription]

I can virutally guarantee this guy consulted at Angelo & Maxie's in the RTC*. They are very slick in that place -- they sold me water seamlessly, but mostly because I wasn't expecting it. They need to be slick. It's an incredibly expensive place, and when I was there on a Thursday, it was only half full. That may not sound unusual, but last year, the only time restaurants that weren't awful didn't have a wait would be on Monday or Tuesday nights. And sometimes they had a wait then too.

*This was the place that was allegedly to be blown up in Arlington Road. It is not a mall, but does exist in concept.