Do not unfold your dinner napkin and place it on your lap until the hostess does
Unfold your dinner napkin discreetly and place it (folded in half lengthwise) on your lap
When you leave the table during dinner, place your napkin on your chair
When dinner is over, the hostess will signify that everyone is finished by placing her napkin to the left of her place setting; you should follow suit and do the same
Remember, napkins are not handkerchiefs, never use them for your nose