If you've been writing for a long time, you've probably once or twice advised a bona fide teacher of writing or a Beta Reader to write about what you know. They usually think they're writing about things you've experienced. Although it is good to write what you know, you do not have to experience it to know it.
When I attended the University of Nebraska, I knew a science fiction writer named Cindy who had two stories published in the Analog magazine. One of those stories was criticized by the professor who writes from what I have been attending. The professor warned her to "write what she knows", and apparently was skeptical that alternative reality was something Cindy understood. This story became her first published fiction.
Although some writers have written a great fiction that grew out of their experiences, for most of us there are research. The research can range from little to intense.
As I studied, I wrote a story for a writing workshop about the guard who was cleaning the morgue during the cemetery shift. He has a habit of drinking at work and is a little drunk, so he believes that one of the bodies that turned out for the early morning autopsy is really alive, but in a coma. I've never been to the morgue so I called the Lincoln General Hospital and asked if I could come and see. A nice guy showed me around the morgue (the first thing I learned was that they did not like being called a morgue, it was a sign on the door, "Clinical assessment"), and I went home and wrote a story.
It turned out that one of my colleagues was in fact a gravitational shift guard at Lincoln General. He thought I was working there at one point. When I told him that I had just finished my research, he said that I smashed him. He asked if he still has that brain barrel … I said no, only jars containing bits of organs in the closet.
"Clinical evaluation" became my first published story, which appeared in an anthology of Pig Iron Press in 1983 New Surrealists .
Arthur Hailey was an example of a writer whose background was almost completely researched. Author of such bestseller Airport, Hotel , and The Moneychangers , Hailey would choose the industry, spend months in deep research, and set up a story in that industry. Although Hailey was a pilot, he did not have much personal experience (and most of his time did not have personal experience) about the things he was writing about. But no one could accuse Arthur Hailey of writing about things he did not know.
Whatever you write, you can fill in parts you do not know about research. Sometimes what you have not experienced can be a big part of the story.
When you research, use "living" rather than "dead" sources as much as you can, or how much you need. A dead source is anything you find in a book, an article in a journal, a document, on the Internet, or anywhere else in it. The live source is when you receive information by talking to people who have had the experience you are writing about. In the above examples, Cindy used dead sources – and her imagination – to correct her story of science fiction; Arthur Hailey and I used live sources for our research.
Make sure your research is thorough. Dean Koontz is another example of a writer who works extensively. He warns reporters to be sure he will get the tiniest details – one of his novels had to find out the color of taxis in a certain Japanese city. Do not assume you know something; find out. I thought that the jargon was "blown away" by descriptive what was happening when someone was shot; The bullet's force stabs the victim. Then I was researching him for the novel I wrote. As it turns out, you have to use a pretty large pistol to make it happen. I mean a serious big pistol. If, for example, you shot somebody with a Magnum of 357 or a shotgun, he would only fall as a potato sack, and would not fly off his legs, as in a movie that will remain without a name.
That's something somebody will know about, and it's embarrassing to be in the book signing and – paraphrase Raja Bradbury – let one of your readers say: "Man, on page 227 Joe is shot and throws him over the couch …" and you say "Yes," and he says, "No."
So write what you know, but you do not have to personally experience it to know it. You know what I mean?