1. Start sparkling conversations -- and end painful ones.
Make fun, harmlessly embarrassing introductions. Say something like, "Susie is a closet Olivia Newton-John fan," suggests Philip Galanes, The New York Times' "Social Q's" etiquette columnist. If guests are getting too acquainted (think heated political debate) and you can't just change the subject, separate them. Ask one to stir the hollandaise, put out a grease fire -- whatever it takes.
2. Smile when an unexpected dinner guest arrives. Set another place. (Curse under your breath -- quietly.)
If need be, redistribute entrées and serve another side dish—but no guilt trips. "Presume the guest has no idea he wasn't invited," says Jodi R. R. Smith, author of From Clueless to Class Act: Manners for the Modern Woman. (Is the guest who brought him a repeat plus-one offender? Have a private chat later.)
3. Play nice with the demon child tearing through your home.
When a guest's toddler is clutching a glass of grape juice and running on your white carpet, don't freak. Instead, try Galanes' tack: "I pretend I'm tremendously concerned for the child," he says. "If I think she's going to break my vase, I'll say, 'I'm afraid she'll cut herself.'" Smith likes setting house rules, such as, "At Aunt Jodi's, we only have drinks in the kitchen." And next time, buy white grape juice.
4. Politely send no-longer-wanted guests on their way.
If the problem is a too-tipsy friend, first put away the alcohol and see that the person gets home safely, says Peggy Post, author of Emily Post's Etiquette, 17th edition. (Not to get all after-school-special, but don't let over-imbibers drive. Full stop.) If you've got a loiterer, Smith suggests subtlety: "Turn up the lights, turn off the music." Nothing? Thank her for coming and get her coat.
5. Give guests time to RSVP -- then start nudging.
For formal to-dos like weddings and bar mitzvahs, send invitations six to eight weeks prior, and ask for RSVPs two weeks before. For casual parties, it's your call: Ask for responses from a week to two days before, whatever you're comfortable with. If you haven't heard from folks, Smith advises playing the "lost invitation" card -- even if you suspect they're dodging.
Whether you're the host or the guest, send the right message -- via the right medium.
Send a note when ...
-- You've attended a formal party.
-- You've eaten at your boss's house, been a houseguest or received a gift.
-- You've behaved clumsily or rudely (e.g., told an off-color joke).
Send an e-mail when ...
-- You're hosting a casual party.
-- You've attended a casual party.
-- You don't think you’ll get around to penning a formal note -- e-mail is better than nothing.
Send a text when ...
-- You want to get the word out for an impromptu gathering.
-- You've attended a casual party whose host you text regularly anyway.