When young people ask me for career advice, I always tell them: "Don't just focus on your own accomplishments. Be a collaborator."

Through a decade of teaching and research at Harvard's business and law schools, I discovered an important and often overlooked insight: People who figured out how to collaborate across teams gained a major competitive edge over those who did not.

The advantages of collaboration skills

When it comes to hiring, smart collaborators are highly desirable candidates. They deliver higher quality results, get promoted faster, are more noticed by senior management, and have more satisfied clients.

But here's what shocked me the most: Collaboration skills are surprisingly rare, especially among men.

A 2021 McKinsey study found that women leaders, compared with men at their same level, were about twice as likely to spend substantial time on collaborative efforts that fell outside their formal job.

How to be an exceptional collaborator

Being a collaborator isn't easy. But the primary goal is simple: bringing people together to solve problems and learn something new.

Here's how to get better at it:

1. Be an inclusive leader

Whether or not you're the project leader, take steps to draw diverse people together.

The mindset I always have is: "That person thinks differently from me. They know something different that I don't, and I can learn a lot from them."

These people shouldn't just have different knowledge domains. They should also represent different professional backgrounds, ages and life experiences.

2. Show appreciation and acknowledgement

A groundbreaking study by Harvard Business School professor Boris Groysbergfound that workers, especially men, often take their professional networks for granted.

During job interviews, because they failed to appreciate how much support they received from their colleagues, they believed they were more independent and "portable" than they actually were.

This "me-first" mentality is often a dealbreaker — and turnoff — for hiring managers. Even Claire Hughes Johnson, a former Google VP of 10 years, says she looks for self-awareness and collaboration skills "before anything else."

3. Ask for help

If you're in charge of presenting a sales report every week, but do it solely on your own, that could suggest you think your opinion is the most valuable.

But if you reach out to experts across different departments for insights, your data points will likely be more compelling.

Don't forget to mention the names of those who contributed, as well as their expertise. This will give your report more credibility.

4. Crowdsource

Give people a way to learn without having to be part of every team. My research found that a desire to learn is a frequent driver of voluntary commitment.

Communities created through Slack and similar messaging tools are a great way to spur virtual forms of collaboration, knowledge sharing, and knowledge distribution.

5. Share data streams

Scorecards and dashboards are powerful tools for several reasons:

Consider which data should be shared, and when, and how. The point is not to hide data, but rather to make it accessible and useful to specific audiences. A good rule of thumb: err on the side of oversharing.

Heidi K. Gardner, PhD, is a Distinguished Fellow at Harvard Law School's Center on the Legal Profession and Program Chair of the Sector Leadership Master Class. Previously, she was a professor at Harvard Business School. She is also the coauthor of the bestselling book "Smarter Collaboration." Heidi earned master's degree from the London School of Economics, and a second PhD from London Business School. Follow her on Twitter.

CNBC