One of the issues with parties, unless you’re the most gregarious of extroverts, is that feeling when you’re about to walk into one but don’t know a single person there. Or perhaps you’re only vaguely connected to the host, who will surely be busy hosting. How do you start a conversation at a party with a complete stranger or someone you barely know? What if you do something horribly wrong, requiring you to sever all relationships and perhaps even move to an entirely new town or galaxy?

But there’s a reason you’re going to this thing. If there isn’t, you should think about not going.

“Say no if you want to say no, and save yourself the agony of canceling,” said Morra Aarons-Mele , author of “ Hiding in the Bathroom: An Introvert’s Roadmap to Getting Out There (When You’d Rather Stay Home) .”

But let’s assume you do want to go, at least a little bit more than you don’t. Take a moment to identify, realistically, what your purpose is for going. Is it:

To make a business connection?

To meet a new friend?

To relax?

To have a good conversation?

To taste some new food or wine?

“If I’m going to a party where it’s more work than fun, I might prep for it differently,” Ms. Aarons-Mele said. “There’s no shame in that.”

After you define your purpose, it becomes easier to set a goal for attending the party. Then you know what you want to accomplish before you have to leave.

Debra Fine , speaker and author of “ The Fine Art of Small Talk ,” likes to give herself a task at any party — for example, meeting three new people.

“Once I do that, I can get a drink, I can leave,” Ms. Fine said. “You get to pick.”

For Ms. Aarons-Mele, after she’s met her goal, “I’ll come home early, take a bath and enjoy alone time.”

Another tip: Give yourself a head start regarding potential conversations and mingling opportunities — and, ideally, quell nerves — by thinking about who else will be attending. “Ask your friend who’s going to be there, review in your mind who might be there,” Ms. Fine said. Then you can come up with topics to start a conversation: Did someone recently get a new job? Have a baby? Share photos of a vacation on social media?