Here are five rules that should be followed when displaying an American flag at your business:
Using a flag pole. There are several rules for flying the flag on a flagpole. If flown in a group of flags with state, local or group flags, the U.S. flag should always be the highest, and should be raised first and lowered last. If flown with the flag of another nation, the flags should never be flown on the same pole, and the flags should be of even height, with the U.S. always to it's own right (the viewer's left).
Using the flag in advertising. The flag code is pretty unequivocal about using the flag for advertising purposes: "The flag should never be used for advertising purposes in any manner whatsoever. It should not be embroidered on such articles as cushions or handkerchiefs and the like, printed or otherwise impressed on paper napkins or boxes or anything that is designed for temporary use and discard."
The flag at night. Contrary to what you might have heard, you can fly your flag at night. However, it must be illuminated. Also, the flag should be removed during inclement weather, unless it is an all-weather flag, which according to the the American Flag Foundation means the flag is made of nylon, or other non-absorbent material.
From a car. If displayed from a car, a flag should be flown from a staff and not draped. The staff should also be affixed to the chassis or attached to the fender on the car's right side.
Though the Flag Code is merely advisory (meaning you won't get put in jail for violating it), Flag Day is a great day to remember what the flag represents and treat it with the dignity and respect it deserves.