Our Self-Improvement Month concludes with a man whose entire life and career are one big pile of self-improvement. Nutrition? Check. Bizarre physical activities? Check. Working less and earning more? Check. Tim Ferriss, creator of the Four-Hour universe, may at first glance look like a charlatan, but it seems more likely that he's a wizard -- and the kind of self-improvement ally we all want on our side.

The psychologist Angela Duckworth argues that a person's level of stick-to-itiveness is directly related to their level of success. No big surprise there. But grit, she says, isn't something you're born with -- it can be learned. Here's how.