Don Yaeger has received his fair share of inspirational advice.
As someone who has spent his career studying high performers, first as a sports journalist and then as the author of numerous celebrity biographies, he has had firsthand insight into the lives of some of the world's greatest professionals and what makes them so successful.
But of all the tips he's received throughout his decades-long career, there is one that stands out above all the rest, the New York Times bestselling author told CNBC Make It.
It was this: "You'll never outperform your inner circle."
The standout guidance came from legendary University of California, Los Angeles basketball coach John Wooden.
A personal mentor to Yaeger, the late-Wooden one day challenged him to put the advice to the test using a quick exercise, which can be applied by anyone in just a few minutes.
All it takes is a piece of paper and a pen.
Wooden told Yaeger to divide a sheet of paper into three columns, one for each of his main social circles: personal, professional, and a social organization.
In each, he was to list the names of the five people he was closest to within those circles.
Then, at the end of the evening, he was to look at the paper and ask himself: "Are they going where you're going? Are they the kind of people you want on your journey to that place?" Yaeger recalled.
"If they're not, you need to scratch them from the list and create a new circle," Wooden told Yaeger.
The moment was "game-changing" for Yaeger, who from that point started to reconsider with whom he spent his time.
"That became this really big story for me because I began to start to evaluate my inner circle; looking at the people I had around me in every aspect of my life," he explained.
"That was game-changing. If I could pick one anecdote, one story in this journey that's had the most impact on me, it would be that. You will never outperform your inner circle, so always be improving that circle."
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