Diane Sawyer Shares The 'Genius' Marriage Advice She'll Never Forget (VIDEO)

In the 26 years she was married to her husband, Mike Nichols, Diane Sawyer learned plenty of lessons about love, relationships and marriage -- but there's only one she calls "genius." Before Nichols passed away from a heart attack late last year, Sawyer appeared on "Oprah's Master Class" and opened up about some of the best marriage advice she'd ever heard.

Sawyer doesn't like to make sweeping statements about the sole recipe for a good marriage -- because "every marriage is a foreign land," she says -- but the veteran journalist does believe that the marriage advice she learned on the job years ago can truly bolster even the strongest relationships.

"I learned something great on one of the stories I did," she says. "Someone said to me... 'A criticism is just a really bad way of making a request. So why don't you just make the request? Why don't you just say, Could we work out this thing that makes me feel this way?'"

This simple statement had quite the impact on Sawyer. "I thought, 'That's genius!'" she says.

This particular advice was made in regards to marriage specifically, but the veteran journalist says it has a much more universal application. "It's helpful in work too, by the way," she points out. "It's helpful in everything, just to make the request."

As far as her own marriage advice, Sawyer adds that laughter helped keep her relationship strong.

"I know that laughing -- and laughing at the same things and laughing at each other in the same way -- is great," Sawyer says, smiling. "It's sustaining. It's great."

Flashback: Go behind the scenes for a glimpse of what a typical day was like for Sawyer when she anchored ABC's "World News Tonight."