How to Build Up Your Willpower Muscle.Steely resolve and self-control can usher an entrepreneur past the inevitable challenges to long-awaited rewards. But how best to tap into the secret weapon of willpower?

After four years of pushing the proverbial rock—or in his case, frozen burrito—up the entrepreneurial hill, Mike Adair could finally see progress. Sales for his Red's All Natural burritos had grown to the point that he needed a big manufacturing partner to scale up production. A months-long search led to a new factory—and then a blindside tackle by Murphy's Law.

"We realized that they had overpromised and didn't have the ability to do a fraction of what we needed," says Adair, who launched his company, which is based in Franklin, Tenn., on a hunch that the world needed an all-natural burrito, just like the ones his wife made. "They were shorting at least half our orders, and our retailers were threatening to throw us out. We were almost out of money. It was a pretty dark time. I wasn't sleeping. I think I aged 10 years in those four or five months."