Give a clear answer if you're coming or not. The worst thing you can do is appear to be holding out for a better offer. If you have to check with your significant other, just say so and make sure you give the host an answer as soon as possible.
Bring a gift. It shouldn't be lavish or ostentatious. If you're giving flowers, have them sent the day before with a handwritten card, so your host can put them on the table. Other good ideas: a nice bottle of red wine or scotch, fancy chocolates, or an assortment of fine cheeses. A bad idea: Twister.
Never arrive early. Lateness, of course, is also bad, but it's even worse to show up thirty minutes early, where you will inconvenience your harried hosts, who are bound to be in the middle of meal preparation. If you can't be on time, fine, but any more than twenty minutes late is pushing it.
Greet your hosts by name when you arrive. Punching someone on the shoulder and using an anatomically impossible nickname is not an acceptable greeting. Especially if you're greeting someone's mom.
Be a gracious guest. Don't be a hero and insist on helping. Don't wander around the kitchen getting in everyone's way. When asked what you'd like to drink or which kind of soup you'd prefer, don't answer, "Whatever's easiest." The easiest is for you to make up your mind.
Mingle! Don't be the cipher who spends an entire party picking out the cashews from the mixed nuts — if the host isn't around to introduce you to people, it's perfectly acceptable to do it yourself. The only thing worse than an obnoxious guest is a dead-silent, potentially psychotic one who stares blankly at the rest of the party.
Don't touch the TV remote. Or the music on the stereo. Or ask to use the Internet. Just because you were told to make yourself at home doesn't mean you should actually do it.
Offer timely help. If you notice your hosts are frantic — like, say, running out of the kitchen with two arms full of scalding-hot plates that are about to come crashing to the floor — by all means, help out. The same rule also holds true for spills. Feel free to jump into action immediately. Just don't use your nice linen napkin.
Eat when served. It's polite to wait until everyone is served before chowing down, but if your hosts tell you not to wait — don't wait. Nothing is more ridiculous than the polite horror of being the first to eat good food.
Don't smoke. If you absolutely must, then go outside, but come up with a cigarette butt disposal strategy beforehand and be aware that everyone will smell it on you when you return.
Volunteer to help clear the dishes. Don't stack them on the table, though. This isn't a restaurant.
Leave at the right time. Here are some good signs it's time to go: They've run out of booze, the host is yawning, consulting his watch, bickering with his spouse in the kitchen; people are milling around the door; or it's dawn. Then, be quick about it: Grab your things, thank the host, smile, turn, and leave.
Thank them, again. You've done everything correctly up until now: brought a gift, greeted the host, talked to the other guests, eaten a fine meal, left in a graceful manner.... Now grab a piece of paper and a pen and write a quick thank-you note, including one detail from the evening to prove you were actually there. A phone call may seem easier, but it's ultimately awkward — after all, what else are you going to say once you've said thank you? E-mails are too impersonal. (And let's just say that posting on someone's wall in Facebook is utterly wrong.) Go with a note. You'll get invited back next year.
Adapted from "Party Manners" by David Laskin, from the November 1984 issue of Esquire.
