A friend of mine from Northern Colorado Writers, Peter D. Springberg, MD, FACP, has started a new website and blog ("Eat like the Doc does") on healthy living with a focus on healthy eating.
Peter's medical and career credentials are very impressive. Even more important to his healthy lifestyle project and the weight loss manual he is writing, Peter practices what he teaches. He is trim and fit and full of energy.
This is a perfect example of writing what you know.
In addition to this project, Peter is working on a full-length memoir and also writes short stories. I found The Hat Decides at the website Immigrant Journeys. Since this story took place in the late 1800s, and Peter wasn't born until 1941, he had to learn about the historical context and the incident secondhand through stories and research, and then write the tale with dialogue and descriptive words to make it come alive.
This is an example of writing what you don't know.
Don't hesitate to write what you know, especially if you are, like Peter, an expert on a topic that will interest thousands of readers.
But don't let that little dictum we've heard so often--Write what you know--keep you from exploring new worlds in fiction. Listen to the stories of elders, read books in all genres, study nonfiction on topics of interest, and let your imagination run wild. If one certain fiction writer had stuck to what she knew, we wouldn't have Hogwarts, would we?
How about you? Do you stick to what you know? If not, how much time per week do you spend on research for your current project?