We've all heard the stories. Some of us, good gracious, have experienced them: The clueless guest who wanders in two hours after Thanksgiving dinner was to be served or lingers until you have to practically kick him out the door. The brother who passes judgment on your new curtains or spouse along with the gravy. The hostess who pooh-poohs your vegetarian ways and insists you try her turkey.

Kinda makes it hard to be thankful, doesn't it?

No, we can't always equate those special holiday meals with good behavior. In fact, in today's "me" society, says Susan Dunn, a life coach in Dallas, proper etiquette is not often the first thing that comes to mind. Instead, we burp at the table after eating because it feels good, dominate a conversation instead of contributing to it, or pick old fights with our siblings because, well, that's what we always do at a family dinner.

Ms. Dunn says your job as both a host and a guest at Thanksgiving is to make sure that everyone who's at the table, from your 90-year-old grandma to your 2-year-old niece, has a good time. (And yes, she notes, the littlest guests should be seated alongside the big ones, but more on that later.) And you can't achieve that without a few social niceties.

"It's really about keeping the other person comfortable and avoiding those emotional highs and lows," says Ms. Dunn.

So what is acceptable behavior and, perhaps more importantly, what is not? Here, we offer tips for both the people hosting the dinner and those who've been invited to their home to enjoy it. Then, bon apetit!

If you're a guest:

• Be on time. Thanksgiving dinner is usually planned around the moment the turkey comes out of the oven. So arrive, with a smile on your face, when your hosts ask you to. (We're assuming, of course, that you RSVP'd.)

• Bring your appetite. The chef went to a great deal of time and expense to prepare this big meal and will want to see you enjoy it.

• Thank your hosts for the invitation with a small gift. Appropriate offerings include a bottle of wine, a box of nice candy, or a bouquet of pretty flowers -- and include a vase.

• Dress appropriately or, at the very least, be clean and pressed. As a true sign of consideration, advises The Emily Post Institute, dress "one notch up." That means no sweats or ratty jeans.

• Because Thanksgiving is such a big meal, it's perfectly acceptable to ask to contribute a dish. This is especially appropriate, Ms. Post's Web site notes, if you or your party have special needs -- say, you can only eat low-fat or vegetarian dishes. Just make sure it isn't messy and doesn't have to be reheated or reassembled; chances are, both the oven and the counters will be full.

• If you do bring a dish, don't forget to take the serving plate home with you or to pick it up a day or so later -- it's a pain to have to track down the owners of all those unclaimed platters and bowls. To help, put name on piece of tape underneath.

• With so much to prepare, your host may not be able to entertain you 24/7. To stay out of her hair, get out and do something. Work up an appetite with a walk in a park or on a trail, or go ice skating at The Rink at PPG Place, Downtown (11 a.m to 10 p.m., 412-394-3641). While you're there, take in the Fifth Annual Gingerbread House display at Two PPG Place.

• A good guest, says Ms. Dunn, is an active guest, so make sure to mingle. Avoid awkward pauses by asking open-ended questions that keep the conversation going. Safe topics include the weather, movies, the decor and community events.

• Family gatherings can evoke old patterns of doing things and unresolved conflicts. Be the bigger person and bury the hatchet, at least for the day. At a minimum, says Ms. Dunn, prepare yourself for unwelcome comments so you won't react to them.

• If the table doesn't have place cards, ask the hostess where she'd like you to sit. She may have pre-arranged places in mind to encourage conversation. Also, someone is going to be asked to say the blessing, so be prepared -- it might be you.

• Speaking of seating, Ms. Dunn strongly advises against a separate kids' table. "Thanksgiving is such a family occasion," she says, "so the kind thing is to make everyone feel included and honored." Putting children at their own table, she says, makes them feel that they didn't get the "ticket" to the big event.

• Eat and drink in moderation. You don't want to end up passed out on the couch. And please, don't forget to pass.

• Family or non-family, offer to help with cleaning up.

• Follow your hosts' lead as to when the evening is over, says Ms. Dunn. Some subtle signs they're ready to call it a night are yawns or lapses in conversation. And of course, don't forget to say thank you with a phone call or handwritten note the next day.

If you're the host:

• Thanksgiving is stressful enough without having to worry about cooking a bunch of fancy dishes. Plan a realistic, doable menu and do as much as you can ahead of time. You'll be more relaxed and better able to have fun.

• Guests might be reluctant to tell you if they have special dietary concerns. One way to take the pressure off, suggests the Emily Post Institute, is to ask them instead. If they do, ask what they'd like you to prepare or graciously accept their offer to bring along a favorite food -- even if it means tofurkey.

• Practice makes perfect. Try any new recipes ahead of time, so you can work out kinks and see how it tastes.

• Take time to greet guests at the door and then introduce them to other people. If there's some time before dinner, note the editors of Williams-Sonoma's new "Holiday Entertaining," set out light snacks, such as olives or a simple antipasto platter, so guests have something to munch on as they mingle over drinks.

• Keep happy hour simple. Offer beer and wine and one signature drink. Don't forget soda and water, served in flutes or cocktail glasses, for nondrinkers.

• Holidays might lend themselves to finery, but it's perfectly acceptable to mix and match fine china with more casual everyday plates, says Jennifer Sbranti, founder of hostesswiththemostess.com. It'll actually make your table look more interesting.

• Think about lighting. Dim or turn off brash overhead lights and use candles and lamps. Guests, especially if they don't know each other, will be more comfortable if they don't feel like they're under a spotlight, notes Styledash.com. Besides, the warm light will make everything on the table look good.

• Let children participate by making decorations and place cards, setting the table and lighting the candles.

• For large sit-down dinners, set places at the dining table and serve buffet style from a sideboard or even the kitchen counter. If space is an issue, use the table as the buffet and arrange for seating in the living room.

• Direct the conversation away from controversial subjects such as politics and sports, says Ms. Dunn. As host, be prepared to head off unpleasant exchanges among guests.

• When it comes to dessert, serve small portions so your guests don't have to commit to a big hunk of anything, suggests pastry chef Gale Gand in Macy's "Great Gatherings: Star Chefs Entertain at Home" (Book Kitchen, $29.95).