While we’re excited about these reunions, it helps to manage our expectations: Some friends may have had a harder year than we knew and may need support just as we’re ready to move on from the pandemic. We need to brace ourselves for conversations that may take significant mental energy, at a time when our emotional bandwidth is already running low. And we should be ready to address hurt feelings—“Where were you?”—on either side.

“We’ve all been through so much. We’re all so raw. And there is a strong sense of longing,” says Marissa King, a sociologist and professor of organizational behavior at the Yale School of Management, who studies social networks. “This combination makes for a really emotional reconnection.”

Research conducted during the pandemic by Dr. King and colleagues, published in January in the journal Socius, found that people’s inner circles—those they consider their nearest and dearest—shifted during the pandemic: They included more family members and fewer close friends. Twenty percent fewer close friends, to be exact.

Reconnecting will be worth the effort. Research shows that people with solid friendships live healthier, longer lives. Friendship decreases blood pressure and stress, reduces the risk of depression and increases longevity, in large part because someone is watching out for us. According to one recent study, we’re even happier hanging out with friends than we are with our romantic partners or children.

We’ll need some thoughtful strategies to help us reconnect. I spoke to Dr. King, as well as a social psychologist who studies friendship and a linguist who specializes in interpersonal communication to get advice.

Pick your A-team

You only have so much time and energy. We have the capacity to maintain 15 core friendships, with just five of them being the most-intimate, shoulder-to-cry-on types of friends, according to research by Oxford University evolutionary psychologist Robin Dunbar, detailed in his book “Friends: Understanding the Power of Our Most Important Relationships.”

The pandemic presents an opportunity to reconfigure this inner circle. But “it’s going to take a concerted effort to get together,” says Deborah Tannen, a professor of linguistics at Georgetown and author of 11 books on communication, including “You’re the Only One I Can Tell: Inside the Language of Women’s Friendships.” She suggests you make a list of your friends. Identify who you missed the most—and who you didn’t miss much at all.

The list will help you prioritize: Which friends should you reach out to first and try to see most often? It will also change the way you respond when people reach out to you. Once you’ve made your list, you’re more likely to answer the phone when one of your A-Teamers calls, rather than waiting to call back when you may feel more like talking.

Pace yourself

In-person interactions are going to require a level of intensity and concentration we haven’t experienced in a while. We’re out of practice.

The pandemic has taught us a lot—the hard way—about how much connection we need. Extroverts are energized externally—they love being around other people. Introverts become energized internally; they prefer to spend time alone. Ambiverts are a mix of both. It doesn’t matter which you are; most people are eager to reconnect with their friends. But know your limits. And honor them.

Start slow. Dr. Tannen suggests you may want to see one friend a week right now—even if you were someone who liked to see friends every night pre-pandemic. Then gradually build up to a pace you’re comfortable with. Introverts may want to stay slow forever.

Consider making plans with a friend to do an activity—visit a museum, take a bike ride—rather than getting together to talk. It may be less emotionally draining. (Dr. Tannen says men typically prefer doing activities with friends, rather than just talking, anyway.)

And make a plan for your second date soon. Reconnection is not a one-and-done undertaking.

Expect tough emotions

You may be eager to see your friend, down a few cocktails, share some laughs and let off some steam. Your friend may need to cry into his beer. And you might not know this until you get there.

Before the pandemic, we regularly heard about our friends’ lives, including their problems. But we haven’t seen each other for a long time. And while we’ve all had a hard year, some have had it tougher than others. Your friend may be struggling with something you don’t know anything about yet—the death of a loved one, an illness, a relationship on the rocks—and have a real need to talk.

It can come as a shock to learn that a good friend is struggling more than we’ve realized—we’ve been so focused on our own issues this past year. Before I reconnect with a friend now, I remind myself that he or she may be in a different emotional place than I am. This helps me gather my emotional energy, focus on catching up on a meaningful level, and be ready to be supportive.

Address hurt feelings

If you haven’t talked to your friends since before the pandemic, there may be some resentment or confusion, on either side. You may feel that your friend hasn’t been there for you. Or she may feel that way about you.

You need to forgive your friends for not being there—and forgive yourself for the same, says Yale’s Dr. King, author of “Social Chemistry: Decoding Patterns of Human Connection.” “We’ve all been through so much—and each person’s individual circumstances really contributed to whether they were in touch or not.” She says to remember the situation was the problem, not the person.

You can address the issue head-on. Tell your friend: “I feel bad. I really miss you. But it was a tough year. I’m glad we’re back in touch now.”

Look forward

The point of reconnecting with friends is to add some joy back into your life, says Mahzad Hojjat, a social psychologist, professor of psychology at the University of Massachusetts Dartmouth, and co-editor of “The Psychology of Friendship.”

So after you’ve caught up on the past year, look to the future. Dr. Hojjat recommends talking about what you’re looking forward to. Ask questions: Is your friend planning a vacation, eager to visit family or see a concert? What is he or she most excited to do now? And—this is important—what would you like to do again together?

“We’ve seen so many negatives this year,” Dr. Hojjat says. “It’s time to focus on the positive.”

Write to Elizabeth Bernstein at elizabeth.bernstein@wsj.com or follow her on Facebook, Twitter or Instagram at EBernsteinWSJ