Everyone says to write what you know, but sometimes that just is not possible. I prefer to think of writing choice to reflect writing about what you love. If you love dogs, then write about them. Even if you know very little, there is something called “research” that will help you make your writing authentic. If you are writing non-fiction, then I can agree about knowing your subject. But, in the fiction genres, loving your subject is crucial to finishing that piece you’re chiseling out word by word.
Loving your subject will help carry you across the mid-project doldrums, get you through the editing process in some type of condition you can still live with yourself after all the temper flares and disagreements, and help you celebrate your release of the work into the wild world of publishing. Loving what you write will make your work sparkle, because the passion you experience in yourself will translate onto the page and resonate with your readers. Think back to when you were in school – the teachers who loved their subject matter. Didn’t you look forward to going to class, even if it was the worst subject? I’ll even bet you made better grades in those classes than you expected too. In part, it was the instructor. But, part of that would have been the selected text. The same principle applies to fiction as well.
If you are struggling with your current project, and the shiny seems to have worn off, then it might be time to take a step back and evaluate your efforts. Are you writing what you know? Has the project become stale, and a chore? Are you slogging through one unappetizing chapter after another? If so, and you do not love your story, then it may be time to let it sit fallow for a while. Especially for those of us with many loves. Don’t forget about it, but set it aside for a week or so. Then, when you come back to it, the likelihood of remembering why you love the story so much is much greater.