R.s.v.p. promptly. Yes, we all lead busy lives, but it is patently unfair to leave your host hanging about whether or not you plan to attend their dinner party. Oftentimes, the hosts are aiming for a certain number of guests around the table, so if you decline, they may well wish to invite another guest to take your spot. Once you have accepted an invitation, you are obligated to keep the date, unless you become very ill or get invited to the White House. “Something better came along” does not qualify as a reason to back out of an invitation to dinner!
Show up on time. By “on time”, I mean not late, but not early either. The host of a party works hard to create a special ambiance, while making it all appear effortless. The guest who arrives twenty minutes early will find the candles unlit, the host walking around with wet hair from his shower, and the hostess frantically searching for those cute little earrings she picked up at her favorite jewelry store in Raleigh. Your hosts will be less than thrilled to have a guest to attend to while they are running around putting the finishing touches on their party.
Of course, being late is just as bad. It is one thing to arrive “fashionably late” to a cocktail party or an open house, but if dinner is being served, it is rude to be late and keep everyone waiting. The roast will be overcooked, the hostess anxious (“How much longer should we wait before we serve dinner?”), and the rest of the guests will be irritated with you. If you realize that you will be more than ten to fifteen minutes late, call your host, apologize profusely for being tardy, and insist that they start dinner without you. When you do arrive, slip into dinner as unobtrusively as possible.
Offer a small gift. A bottle of wine or a box of fine chocolates can properly be brought to the dinner party, but if you plan to give flowers, it is most polite to have them delivered to the house in advance of the party. That way your host does not have to drop everything to search for a vase when you arrive at the door. It is also fine to think more creatively about a hostess gift. A beautiful hardcover book, a small gift from the jewelry store in Raleigh your hostess likes, or a gift for the kitchen like a handcrafted wooden cutting board all make great dinner party presents. Don't feel like you have to spend a lot of cash either, just pick a charming little trinket that will make your hosts smile.
Be a good conversationalist. The flow of conversation around the dinner table will make or break a dinner party. Do your best to be engaging, to speak to the guests on either side of you, and to avoid controversial topics like religion and politics. Don't be surprised if you are not seated beside your spouse; it is customary to break up married couples to encourage all the guests to chat with each other. If you have no idea what to talk about, read the newspaper the morning of the party to brush up on current events.
Finally, send a thank you note! Let your hosts know how much you enjoyed their party by sending a brief thank you note the next day. And last but not least, plan to reciprocate with an invitation of your own sometime in the near future.