For example, I like to work on various community service projects. In recent years, I've volunteered as a construction worker and photographer for Habitat for Humanity Tucson. I’ve also been a post-Katrina reconstruction volunteer in Mississippi. Neither of these activities would be possible if I was tied to a job where I’d have to ask for time off.

The most important lesson that I've learned is that it's not enough to be IN business. You must also be a student OF business.

So, in addition to your business career, commit yourself to a career of lifelong learning. Read books, newspapers, magazines, websites, blogs. Take classes, seminars, and workshops. Listen to the news. Pay attention to what the media are telling you -- and what they are not. And get to know people who've been in business for many years. They will be some of the best teachers you'll ever have.

I want to encourage you to learn and do as many different things as possible. Life lasts a long time. You can never be too sure about what you need to know out there.

Case in point: I make my living as a designer. A while back, I was designing a postcard, and wanted to add an accent to the lettering in the card. But nothing I tried had the right look. So, I decided to apply a bit of knowledge that I'd gained in a college calculus class. Voila, the accent came out perfectly.

This graphic designer is very glad that she has the problem-solving tools of calculus at her disposal. And she's even more grateful for the four years of high school math that enabled her to succeed in college calculus.