There are a couple of cliches that get thrown at writers all the time, one of the most common being "write what you know." It's like the first piece of advice given to all writers and is, I think, one of the worst. The idea is that if you write about a subject matter in which you are well-versed and knowledgeable...something. I don't know what. You'll write well, I guess. Me, I think this is bollocks. Bad advice. Wrong and wrong-headed. Et cetera.
Writing about what you know will likely allow you to write at great length about subjects that don't inspire you, that don't challenge you, that are not particularly interesting to you. That's a recipe for bad, dull fiction. For example, I know a lot about spreadsheets. Should I write about that? No, I didn't think so. How about discretionary spending on grant budgets? No? How about expression matching in PERL? No! "Writing what I know" will not yield compelling stories or good fiction.
What I think we should do is write about what we care about. Write about what fascinates us, even if we know nothing about it. If we're really interested, we'll do the research and get smart about our subject, because we'll have a passion to find out the facts and the history and the details, and our writing will be informed by that passion.
Or, as John Gardner put it (so much better than I have), "Nothing can be more limiting to the imagination, nothing is quicker to turn on the psyche’s censoring devices and distortion systems, than trying to write truthfully and interestingly about one’s own home town, one’s Episcopalian mother, one’s crippled younger sister.”
And really, more to the point, good fiction is less about subject matter than it is about character. We should write about characters that we care about and in whom we are interested, and because we care and are interested, that care and interest will be translated into our writing and to our readers.
I'd like very much to lead a campaign to eliminate the "write what you know" advice. If someone is a beginning writer and asks you for advice, don't tell them to write what they know; tell them to write what they care about, what they are interested in, and tell them to write it the way their favorite writers would do it.
I was going to write about details, but this seemed more important today. Maybe I'll write about details on Friday, when everyone is out shopping. We'll see.