September marks eight years since I resigned from my vice president position at a global public relations firm and made a go of it on my own. What a ride it’s been—a growing staff, a beautiful office, more than a dozen awards in just a few years, “rightsizing” in this new economy.

Stress? Check.

Gray hair (at times)? Check.

Exhilarating and rewarding? Check, check, check.

Recently, I reconnected with an old colleague who is contemplating striking out on her own, and she asked for my advice. So I’ve reflected on what I will tell her—and anyone—looking to harness their entrepreneurial spirit in public relations...