Or: So, there are actually bespectacled wizards, dragons, aliens, time-travelers and kind-hearted real estate agents all around us?
I understand where this piece of advice is coming from. The more you know about a topic, the more realistic your setting and characters will be. Like, for example, your protagonist is a lawyer and she has a trial. It’s customary for you to know the procedure so that when actual lawyers read it, they won’t be put off. The same goes for all other professions, apparently. So, does this mean that you can only write out a murder scene after you’ve killed someone?
Well, the thing is, writers can work really fast when writing about what they know, but they have to do a bunch of stuff before writing about what they don’t. You have a guitarist as your main character but you don’t even know how many strings a guitar has? Before having them change careers, do your freaking research. First off, google some images. (The answer is six, by the way. Six strings!) Watch some videos of shows or inteviews, listen to some guitar solos, see how the musicians’ faces change when they perform or talk about their art, and write about that.
You cannot know what people’s work description entails if you haven’t done it yourself. So, let people who have help you through it. But, please, don’t start hobnobbing with any serial killers, ok? There’s a chance you might not live long enough to write about their trade, just saying.
You probably think all the above only apply when writing contemporary fiction. Because, you know, if you write fantasy, sky is the limit, right?
Fantasy writers also need to do research. But instead of manuals, history books and documentaries, they will have to see what’s already out there. I can guarantee you that whoever writes anything about zombies, they have definitely seen at least a zombie movie or two. The good thing about fantasy, though, is that you can tweak some elements. Like for example, your vampires might be immune to sunlight or the only reason they hate garlic is bad breath. But they will always drink blood. You know this, because you’ve done your research. Well done, you.
So, generally, don’t write what you know. Write what you learn.