Imagine that you have been accepted to Harvard Business School. The ivy-covered buildings and high-powered faculty whisper that all you need to do is listen to your teachers, get good grades and work well with your peers. After two years, you'll emerge ready to take the business world by storm. Once you have that degree, you'll have it made.

But don't kid yourself. What matters exponentially more than that M.B.A. is the set of skills and accomplishments that got you into business school in the first place. What if those same...