In "Ten Minute Toughness," Jason Selk gives readers a 'how to' guide to improving mental toughness, including developing a highlight reel for visualizing success. Whatever your field, you can recall your preparation, execution, and emotions when you achieved success. You can draw upon those resources to facilitate future success.
Coach Terry Horn presents a summary here.
I have given players notebooks to write down what they learn, what they have done well (three items) in a practice or game, and ONE need area and specifically what they will do to improve that area.
Coach Starkey shares Five Characteristics for Success in Sports. Not surprisingly, they don't include being the swiftest or the strongest.
The key attributes are psychological - passion, positivity, curiosity (teachable), self-motivation, and discipline. If you want to change the world, then you have to change yourself.