The advice given here is good, but is US-specific. For those with this predicament in the UK, if you’re in a bar then the correct procedure is to say “And one for yourself”—this allows the bartender to take between a nominal tip and the cost of the drink. Tipping is less common in British bars than USian ones, but not unknown. Restaurant tipping follows the same rules as the US.
The advice given here is good, but is US-specific. For those with this predicament in the UK, if you’re in a bar then the correct procedure is to say “And one for yourself”—this allows the bartender to take between a nominal tip and the cost of the drink. Tipping is less common in British bars than USian ones, but not unknown. Restaurant tipping follows the same rules as the US.
A complete guide to English pub etiquette can be found at http://real-ale.dreamwidth.org/1252.html