I admit that the title of this column is a bit hyperbolic. Surely, somebody will care if you write what you know: Your parents, your grandmother, your beloved pet, maybe even some of your friends. They love you. They are in your corner. Moreover, some of what you know is what they also know, so for them your comments may be self-affirming or at least self-referential. It is like being tagged by your best friend in something he has posted on Facebook. You will want to see what he has put up there because deep down you think it may say something about you, or at the very least you will learn something more about a person who matters to you.
The problem with writing what you know for a general audience is that the vast majority of readers will not know you. They have no vested interest in you as a person, your story or commentary, or your success as a writer. Sometimes, they will be outright hostile, but most often they are just indifferent. This may seem obvious, but as a prolific writer I know from experience that when I am writing something I presume the reader is a friend or at least an interested person. I imagine speaking to someone I know. This helps me write in a more intimate or conversational manner. What I have had to remember is that that writing technique, though helpful, should not be confused with reality. In fact, if I actually get more than a single digit number of readers, most of them will not know me or care to know me.
In a positive sense, writing what you know can mean two things: Write what you have some experience or expertise in, or include details in your imagined scene from real life experience so that the scene reads as more “realistic” or “compelling.” Both are valid points. Tom Clancy would not have had the success he had if he was not also an expert on military history, tactics, and hardware. His novels benefitted from his ability to write what he knew in that narrow field. As for the second point, good writers always tap into their memories to add color to the scenes or scenarios they write. When I am introducing a new character, I often give him or her physical or personality traits I observed in real life people I know.
Good stories combine memories with imagination, and better stories rely more on the latter than the former. The exception is if you are writing out a scene, scenario, or story that is meant to be autobiographical, though even then you will often embellish the true life account with some imaginative flair to make it “better” on paper than it really was. Putting aside autobiography, the problem with writing what you know is that you put too much focus on your own personal memories and not enough on your imagination. If you do not catch yourself doing this, the writing may become too insular. The characters may become too obviously self-referential. The scenarios, which may have meant a lot to you the writer, will not be compelling enough to excite the reader’s imagination.
For stories to work, the readers must be even more invested in the outcomes of those stories than the writers. More likely this will happen if the writer focuses his or her craft on good storytelling techniques and on effective use of imagination. Stephen King does not “write what he knows” when he crafts a compelling monster or serial killer (Thank God). Yes, he often taps into his personal life experiences with how he describes a small, quaint town or an interpersonal family dynamic, but he is effective more so because of his superior technique and imagination.
For the most part, my advice is not to write what you know. Instead, think about what you know as just one tool in your box. You can use that tool to exhibit some expertise in a subject matter, or to add more color to an imagined character. Just do not confuse the tool in the box with what is on the canvas. Most readers do not care about the bright and shiny tool in your box. They care about the completed artwork and what it does to their own imagination.