Among age old advice that includes ‘Show, don’t tell’ there is a specific one that I want to contradict today.
Write what you know.
I’m going to go out into the line of fire and change that around. Write what you don’t know.
Now, I’m not saying stop writing what you know, I’m merely adding that it shouldn’t be mutually exclusive. If you look at the matter closely, you’ll notice that by writing what you don’t know will eventually turn into writing what you do know, thus completing the cycle and fulfilling the rule.
Writing outside your genre is perhaps one of the best ways to expand your knowledge. Who knows, you might find that you enjoy writing mysteries more than you do fantasy. You can even go as far as dabbling in poetry to see if your creative niche fits in there somewhere.
I’d like to expand a bit and add: write what you’re bad at and write what you haven’t tried before.
By writing what you’re bad at – for example writing from the opposite gender POV – you will gain practice and get better at it. For example, I do in fact, suck at writing female perspective, so I’m currently working on a novel with a female protagonist. Does is currently suck? Yes. But I get better the farther I go. (Novel length is good, since it gives you lots of practice*)
Experiment a bit, and write outside your groove. Let’s say most of your stories are epic-proportioned plot-based fiction. Swing that around and challenge yourself by writing a character-driven story that is set inside a bomb shelter.
Change everything you can, including but not limited to : Setting, amount of characters, POV, suspense, character or plot driven. By getting out of your groove, you’ll learn how to do new things, and maybe find out that you like it. It will give you a wider scope of reference to pump out that best-selling novel that rests inside your heart.
*If novel length just to practice is a bit long for you, short stories work just as well.