As we head into the holiday season, and what I like to call the Iditarod of Parties, I’ve been thinking about group dynamics and what makes for a great soirée. Let’s face it: Nothing is more boring than attending the same dinner party with the same guests over and over.

Last month, Denise Rich told us her perfect guest list includes 60 percent people who know each other and 40 percent who don’t. That can be tricky to achieve, but well worth the effort. As you plan your upcoming get-togethers, think about shaking up your circles of friends and going just slightly out of your comfort zone. Consider inviting a few people whom you’d like to get to know better. The conversations around the room are sure to be more interesting if there are new acquaintances and unexpected combinations.

Seating is another key element to keeping the evening lively. One rule I swear by is to never seat couples together. And when there are multiple tables, I put them at different tables. Think of how much more the couples themselves will have to talk about during the drive home that night!

Gracious seating plans are easily carried out with place cards. Think of them as your dual-purpose little helpers. Place cards make your guests feel welcome and planned for and they enable you to mix up the crowd. Just remember the onus is on you to circulate among your guests and make introductions during the cocktail hour before dinner. Don’t worry about introducing everyone. The act of the hosts welcoming each person and making them feel comfortable will create an open atmosphere where guests are likely to mingle with ease.

And finally, if you’re likely to be a guest as often as a host this season, keep this advise from Ms. Rich in mind: “Go over to the side of the room and talk to the person you least want to talk to,” she advises. “When you talk to people who you may not expect to connect with, something unusual can happen.”