Accept the fact that when you start down this road, Literature Elitists will tell you that you’re writing something vaguely below toddler’s entertainment, while the rest of the world will ask if you’re writing something like Harry Potter or Twilight or Game of Thrones. Treat both with respect and patience. They’ll catch on eventually.
Begin at the beginning of your story, not the beginning of time. We don’t need to know how the gods formed man out of clay and spit and blood and luck, before we know your main character’s name. We definitely don’t need to hear the story of how the High King god’s favorite son’s favorite dog gnawed on the sky in its puppy-teething-period, and bit pinprick star holes into the blackness, before we know your main character’s name.
Can’t – shouldn’t, mustn’t, often dare to, but really, really can’t – break your own rules. This is your world, and you can say that gravity pulls sideways if you want, but if you come back later and try to say that gravity pulls upwards, downwards, the other sideways, or in a curlicue that mostly resembles a drunken hurricane, you’d better make your book durable, because your audience will spend a lot of time throwing it across a room.
Destroy that box you’ve been building around your imagination. Anything is fair game, today. Did you not just hear me say that you could turn gravity around? That would be quite a natural disaster adventure, with everyone hanging off the mountains for dear life…
Get to know your new imaginary world. Memorize it. Know every detail. Convince your readers that you’ve actually been there, with the way you describe the people, and the trees, and the sunset, and the food, and the parties, and the fights, the blood, the battles, and the heartache.
Hats, scarves, socks, coats, and mittens are not new inventions. Even if you’ve only seen fantasy characters riding down the dark plains in cloaks, it doesn’t mean you can’t have a dashing hero in her cap. Decide for yourself what you want in your world.
Include something that you have fallen in love with. Not something that you think is cool. Not something that you think will grab someone else’s attention. Something that you have picked up and handled, put down and come back to, held close to your chest and guarded, smiled at, and laughed with, and cried for. Something that you love. Include a dozen things that you have fallen in love with, if you can.
Justifying that this is a fantasy world by adding dragons and fairies, is not necessary. Everyone being able to point at your story and call it fantasy, is also not necessary. “Fantasy” as a genre, is more like a target painted on a comet that keeps getting pushed and pulled by the gravitational forces and unobservable winds of the universe, lighting random objects on fire as it goes. You don’t have to aim to ride the obnoxious comet. Just aim to be on fire.
Keep writing. Keep writing. Keep writing. More than any other kind of story, this is an experiment to see how much you can talk a reader into believing your lies. The only way to know if your trick worked, is to follow it through to the end.
Quick! Color code your characters. Red for magic users. Black for evil. Blue or Green or White for good (because everyone knows there are more diverse kinds of good than evil). Gray and Brown for anyone inconsequential that the reader is supposed to overlook. Or… you know…
Read. Everything. Read fantasy books, so you know what’s been done and how it works. Read myths and folklore and legends. Read other fiction books that do what they do well. Read history books, so you can see what reality is like. Read science books so that you can see how reality works. Read books in other languages so you can see what subtle difference is. Read your toaster manual so you don’t accidentally light your house on fire in the middle of a crucial writing moment.
Watch out for words like “sparkle” or “disappear.” In other writing they might be immediately recognized as metaphorical, but in fantasy, you might mistakenly tell a reader that your hero’s smile literally sparkled as she literally disappeared into a ray of literal sunshine. Literally.
Xenophthalmia is a large, strange, exciting, made-up sounding word. It might make an excellent country name in your story. Or an excellent magic spell for disarming your villain. Or an insult for when you really just want to tick him off. It’s also the technical word for when your eye puffs up because you got something in it. Make sure you aren’t using made-up words that actually have meaning. Readers are smart people.
Your ending must be earned, whether it’s happy, sad, or somewhere in between. Every action in the beginning and middle of your story must have bought those final events, one moment at a time. And the “long-lost parent arrives on a cloud, turns out to be a fairy-like deity, gives the hero a hug and a new sword, and everyone skips into the sunset” ending is too expensive to ever be properly paid for.