One of the really bad things you can do to your writing is to dress up the vocabulary, looking for long words because you’re maybe a little ashamed of your short ones. This is like dressing up a household pet in evening clothes. The pet is embarrassed and the person who committed this act of premeditated cuteness should be even more embarrassed. Make yourself a solemn promise right now that you’ll never use “emolument” when you mean “tip” and you’ll never say John stopped long enough to perform an act of excretion when you mean John stopped long enough to take a sh*t. If you believe “take a sh*t” would be considered offensive or inappropriate to your audience, feel free to say John stopped long enough to move his bowels (or perhaps John stopped long enough to “push”). I’m not trying to get you to talk dirty, only plain and direct. Remember that the basic rule of vocabulary is use the first word that comes to your mind, if it is appropriate and colorful. If you hesitate and cogitate, you will come up with another word — of course you will, there’s always another word — but it probably won’t be as good as your first one, or as close to what you really mean.
This business of meaning is a very big deal. If you doubt it, think of all the times you’ve heard someone say “I just can’t describe it” or “That isn’t what I mean.” Think of all the times you’ve said those things yourself, usually in a tone of mild or serious frustration. The word is only a representation of the meaning; even at its best, writing almost always falls short of full meaning. Given that, why in God’s name would you want to make things worse by choosing a word which is only cousin to the one you really wanted to use?
In terms of genre, it’s probably fair to assume that you will begin by writing what you love to read — certainly I have recounted my early love affair with the EC horror comics until the tale has gone stale. But I did love them, ditto horror movies like I Married a Monster from Outer Space, and the result was stories like “I Was a Teenage Graverobber.” Even today I’m not above writing slightly more sophisticated versions of that tale; I was built with a love of the night and the unquiet coffin, that’s all. If you disapprove, I can only shrug my shoulders. It’s what I have.
If you happen to be a science fiction fan, it’s natural that you should want to write science fiction (and the more sf you’ve read, the less likely it is that you’ll simply revisit the field’s well-mined conventions, such as space opera and dystopian satire). If you’re a mystery fan, you’ll want to write mysteries, and if you enjoy romances, it’s natural for you to want to write romances of your own. There’s nothing wrong with writing any of these things. What would be very wrong, I think, is to turn away from what you know and like (or love, the way I loved those old ECs and black-and-white horror flicks) in favor of things you believe will impress your friends, relatives, and writing-circle colleagues. What’s equally wrong is the deliberate turning toward some genre or type of fiction in order to make money. It’s morally wonky, for one thing — the job of fiction is to find the truth inside the story’s web of lies, not to commit intellectual dishonesty in the hunt for the buck. Also, brothers and sisters, it doesn’t work.
Stylistic imitation is one thing, a perfectly honorable way to get started as a writer (and impossible to avoid, really; some sort of imitation marks each new stage of a writer’s development), but one cannot imitate a writer’s approach to a particular genre, no matter how simple what the writer is doing may seem. You can’t aim a book like a cruise missile, in other words. People who decide to make a fortune writing like John Grisham or Tom Clancy produce nothing but pale imitations, by and large, because vocabulary is not the same things as feeling and plot is light-years from the truth as it is understood by the mind and the heart. When you see a novel with “In the tradition of (John Grisham/Patricia Cornwell/Mary Higgins Clark/Dean Koontz)” on the cover, you know you are looking at one of these overcalculated (and likely boring) imitations.
From On Writing by Stephen King