When a career-ending injury left elite athlete and professional football player Lewis Howes out of work and living on his sister's couch, he decided he needed to make a change for the better. He started by reaching out to people he admired, searching for mentors, and applying his past coaches' advice from sports to life off the field. Lewis did more than bounce back: He built a multimillion-dollar online business and is now a sought-after business coach, speaker, and podcast host.

In The School of Greatness, Howes shares the essential tips and habits he gathered in...