That’s the time-honored advice given to any aspiring writer of non-fiction, fiction poetry, lyric or essay.
Write what you know.
Up until my 52nd birthday, I wrote words for music, press releases for clients and the 
occasional opinion piece. Then I began a memoir, a running diary that began on 9/11/01 and continued for about eighteen months thereafter. At 160,000 words, it’s a mish-mash of styles: the analytical observer trying to record history and the grief-stricken narrator trying to work out her anguish. As my personal ties to the material have loosened, I’ve accepted that the work’s merit lies mostly in its therapeutic value to me. There are some insights worth saving; these I’ve either salvaged for future publication or used as fodder for two of the books I’ve written.
Each of those non-fiction books has grown out of my experience with losing a loved one in an historical event and then fashioning myself as something of a minor player. I’m proud of both Because I Say So: Moral Authority’s Dangerous Appeal and Hope in Small Doses because they represent the intersection of conviction and experience.
Write what you know.
Several years ago, I realized I had no more to say on the seminal but narrow slice of my life represented by the September 11 attacks, which meant that I found myself stuck in the mud just as I was promoting my book on hope (and getting asked specific questions about ground zero or US policy on terrorism or what it was like to be a 9/11 family member—arrgh!). I had a knack for writing; I knew that. With practice, I could get quite good at it. But what was I supposed to write about? What did I know?
I began by enrolling in an established New York writing workshop where the instructor started us on short stories. I loved the work. Writing tales between, say, 1500 and 500 words is liberating. The imposition of length freed me to do other things; to get to the point, to make my words count and my sentences mean something: to be entertaining.
I had lots of ideas for stories about horses and homicidal spinsters, cops and cowboys, telepathic boys and sociopathic girls and a dog worried about being displaced. But while I could fashion my notions into interesting and even entertaining narratives, I was concerned about what my instructor was calling the authenticity of what I was writing. After all, I’m not a horse, housewife, young mother, homicidal spinster, telepathic boy, sociopathic girl or dog.
Write what you know.
Was I writing what I knew? What the hell did I know anyway? I grew up the middle child of a middle class family in a middle class neighborhood in a Midwestern suburb in the middle of the last century. I don’t remember anything interesting happen to me growing up except that which took place in my own slightly dissociative mind. Mildly alienated and marginally different from the other kids, I was nevertheless loved by my family. Where were the mountains to climb, the challenges to overcome, the dramatic or dangerous or debilitating past to throw off in order to emerge stronger, better and more resilient? What did I know of anything? What the hell could I write about? What—other than a single, shocking loss in mid-life—did I have the right to write about?
Write what you know.
Epiphany time, although the epiphany is probably fifteen years in the making: Good writing involves a reveal—not a plot reveal but an author reveal. Put another way, the hardest part of writing isn’t writing what you know but admitting what you know about yourself. One doesn’t have to say it, of course; one just has to show it. Words used as a window, not a door.
It’s not a novel concept, except perhaps for me in my continuing evolution. I don’t need to have lived as a cop or a cowboy or an assassin. Something about those lives will resonate within me. Even if I haven’t climbed a mountain or hiked a trail or met the Dali Lama, I can write about hope, heartbreak, confusion, despair, discovery, joy, tenderness, wonder and pure unadulterated rage.
I can write what I know.