|What is this strange hieroglyphic?|
Another of the rules that people will bring up or give to writers is 'write what you know.' This is one of the most common rules, and its something even people who are not writers and know little about the craft will toss out there.
At first blush it appears easy to understand; you can't write convincing stories about things you are clueless about. You have to understand how a car works to write about a car, you can't write detective fiction if you know nothing about police work or crime.
And certainly many authors have used this to great effect. Loren Estleman, for example, was a crime writer for a Detroit newspaper for years before he began writing the Amos Walker detective novels. Dashiell Hammett was a Pinkerton operative before he wrote his first Sam Spade story.
But at the same time, some authors have excelled at things they had no personal experience in. Raymond Chandler wrote some of the best detective fiction the world has ever seen, and he had no experience as a detective or policeman. Edgar Allen Poe, the man who invented detective novels, only had experience with the police by being arrested.
And if you are a writer of genres such as fantasy, science fiction, or horror, there is no possible way to research or 'know' much of what you're going to write about. Goblins don't exist; man has never been to Alpha Centauri; werewolves are legends you cannot study. Almost nothing HP Lovecraft wrote about is even knowable by the human mind.
And in fact while you can know some aspects of, say, historical writing, there's much you cannot know and must guess at. You can read about and study the clothing worn at the time, but not how it felt to wear or what the dialog of people discussing the clothing was like.
Ultimately, if you're going to write fiction, you must write about things you do not, and often cannot know. So what about that dictum? How can you 'write what you know' about the unknowable?
I think the best way to approach this is to realize that it does not mean you may only write that which you are an exhaustive expert in. Instead it is more about not writing what you know nothing about. You can't actually study goblins in the wild to be a better goblinologist for your fantasy novel. But if you are someone who has only heard the word 'goblin' and have no familiarity even with what they are supposed to be in legend and established fantasy, you can't write about them.
In this context, 'write what you know' means to write what you understand and have a strong intellectual and emotional grasp of. Writing fiction necessarily means writing things you have no clear knowledge of in a scientific and technical sense. Fiction writing is essentially lying in an artistic manner. Not to deceive, but to entertain.
|Tryin' to iceskate up hill again, I see|
So writing what you know in this sense is writing what you have thought through, understand in their context as you have invented them, and have considered carefully. Even Stephanie Meyer who famously said she knew little about Vampires and didn't like them, was able to come up with a compelling and consistent concept of the creatures for her Twilight books. She made her own version, as loathsome as I may find them, and made them her own. So she knew her vampires, well enough to write about them.
A writer can't know what the clash of cultures between the Minrai empire and the Ak'sis*orli tribalists on planet Gsza'ski are like from study, because they were just invented off the top of my head. But a writer can know what clashes of other cultures in the past have been, how prejudices and wars and conflicts develop and play out. From there, that can be applied to other settings and situations.
Ultimately it comes down to less "write what you're an expert in" and more "write what you are comfortable with and can write intuitively in a convincing manner." You don't have to have a doctorate-level comprehension on dragons to write a good story about a dragon, you just have to have thought it through and understand what you want to portray.
Clearly, anything that really exists you can - and must - research as well as you can. If you write about faeries, well you can read up on what people have said about the creatures in the past, but its largely up to your imagination. But if you write about mongols, well you best read and study and learn about them as much as you can before tackling the subject.
Another sense in which you should 'write what you know' is that you ought to write the things you are good at, comfortable with, and understand well. J.R.R. Tolkien was a master of linguistics and medieval literature, so he turned that toward crafting his stories of Middle Earth. Patrick O'Brian became one of the world's foremost experts in the English navy during the Napoleonic wars (truly what could be considered the first "world war"). So he wrote compelling and incredibly informed books about that time period, including language, culture, clothing, food, and so on.
|There is no such thing as too many tools|
Whatever you write, your understanding and skill in other areas will reflect in your writing. You should use that to your advantage, treating it as a specialized tool in your writing toolbelt. This will give your stories authenticity and strength that another may not be able to use as well. If you know mechanics or baseball or computer programming, using those skills in your writing will give it an honesty and truth that will bring the story to a greater level of impact and immersion than it might otherwise.
Ultimately, "write what you know" is about honesty with your readers. If you try to fake it, if you try to write something you aren't comfortable with or have not considered sufficiently, it will show in your writing and your story will suffer for it. Whether its martians or dragons or ghosts, understand your topic and write honestly, or you will be writing poorly. That's all it comes down to.