Generally, American businesspeople are more informal in their work attire than Europeans but in Washington, DC men always wear suits and women stylish and conservative business attire. National and international organisations tend to be more formal, although smaller companies now operate a smart-casual clothes policy (no jeans). 

Appointments for meetings should be made, and punctuality is expected. It is quite common for meetings to be held over lunch, although the prohibitive cost of eating out in the city at traditional business venues means that some companies bring in outside caterers to the office for important, large-scale lunch meetings. 

Business dinners tend to take place in restaurants rather than at home. Cocktails after work are commonplace. There are a large number of bars, particularly around Dupont Circle, which have happy hours until 1900. 

The use of business cards is routine. Though working hours are often much longer, business hours are generally Monday to Friday 0900-1730.