"Find your niche, Mary," a writer/PR friend advised me. I've been writing for years in whatever field brought in income, and have wide experience in many areas. However, nowadays, we're encouraged to find a niche and capitalize on it.
Feather Schwartz Foster has done just this with her research, writing, teaching and speaking about various Presidents' wives and their eras in history. She has turned a hobby into a career. And written books on the topic, such asLadies: a Conjecture of Personalities .
Even more interesting, she now lives in Williamsburg, VA, right in the midst of history and teaches classes there.
By checking out her web site and signing up for her e-newsletter, perhaps you'll gain ideas for promoting a niche of your own.