In the Beginning, there was a dilemma.
So you’ve got this really amazing fantasy novel idea. Maybe you sat down to write a short story and it just exploded on you. Maybe you actually did write a short story and your critique group said “this feels more like a first novel chapter” (that one happens to me all the time). Maybe you’ve just got this burning image in your mind that haunts you every time you drive your car or do the dishes.
Awesome, sit down and start writing, right?
Er… yes and no.
The problem is that fantasy contains too many $*(#&$#$ variables. Granted, if it’s urban fantasy, you’re probably good to go (and I hate you, because I just don’t write urban and it would make my life much easier if I could). But otherwise, you’re kind of SOL, because you can’t write a story set in a world you don’t know anything about. Well, you can, but chances are excellent it’ll end up completely crappy and derivative, and if obvious crappiness is the sort of thing that bothers you, you’ll end up wasting a lot of time trying to remedy your issues in subsequent drafts (says the weary voice of experience. Be smarter than me, please.). Half-assed, Medieval Times world building will hem in your story in unpredictable ways. It will deny you fully-rounded characters and plot possibilities.
Now, I’m not saying I’m against swords or sorcerers. Hell, if I get peckish while I’m reading I’ll most likely grab a mid-book snack of bread and cheese and apple; the only thing saving me from straight-up Hobbitry is that I’m too lazy to be frying any mushrooms. Sad but true.
So it would be fair to say I like high/low/epic fantasy best, and that is why I’m especially critical of it.
The problem with diving head-first into writing fantasy is that you’re gonna get stuck if you don’t do the homework. What’s the climate like? Terrain? Major food sources? Technology levels? Population density? Physical traits (what do these people look like)? Religion(s)? Politics? History? Gender equality? What is a normal family unit? Is queerness a nonissue, or will it get you run out of town? What social taboos are there, then? What about art, music, literature, and other expressions of culture? Figure all that out and you’ve got one race/culture. One. Then you get to suck it up and do it three or four more times, because even if people of other countries/races/cultures do not currently figure into your plot, their existence will inform your work in unconscious ways, especially if you have a large city in there anywhere.
And that’s not even touching the magic, which has to have some rhyme and reason to it, or languages (Though I love etymology, I’m not a big conlanger myself, and thus of the opinion that just making a working vocabulary is enough, so that you can consistently name people and places and create a few good swears).
Even if you end up making a lot of choices that cause your world to resemble medieval Europe, reasoning that this is an alternate earth or is actually our world but set incredibly far in the future, your setting will still have an inherent genuineness to it.I mean, let’s face it, there’s only going to be so much that is strange about your world as it’s hard to get away from oak trees and rabbits and sheep without getting into the weird smeerp thing anyway (warning! that link leads to TV Tropes, see you in six hours). It gets exhausting, so the main thing is to develop the cultures, and not worry too much about the rest. I mean, bread is bread, unless it has some sort of specific quality that makes it different from bread as we know it. Like, it makes you telepathic, or is actually made of the ground up bones of Englishmen. You get the idea.
Worldbuilding is a lot of work, something that is magically onerous and fun simultaneously. But if you want to make a world or a city that people remember, a Middle Earth or a Bas Lag or a Hogwarts or an Oz, you have to do the homework. If an idea for a fantasy novel is burning a hole in your head, by all means dive in, but do your worldbuilding in tandem, and save yourself some grief in the long run.