Writing fantasy is easy. Writing good fantasy is hard. A lot of writers don't really get how much work it is to build a believable world that is not Earth, Earth-normal, or based on "real" history, however skewed. The tired tropes of medieval worlds populated with pre-industrial tech, lords, ladies, petulant princesses and evil overlords are well-trodden, so much so that when you say "fantasy," that is what a lot of the prospective audience instantly thinks of.
I deliberately set out to make Firedancer, coming in September from Sky Warrior Books, something outside all those tropes. It is an alternate world fantasy, which means it isn't set on any version of "Earth" and the only thing familiar is that the people are human. Sort of. I greatly admire writers like C.J. Cherryh who can create wonderful non-human protagonists and make us not only sympathize with them but believe every word. I'm not quite up for creating truly alien protags, but I did create a fantasy world without the usual governing structures, no history of war as we know it, and not a horse, sword, dragon, elf, orc, or evil overlord in sight. The enemies of these people are elementals: Fire, Wind, Water. These human clans have no time to fight each other because their planet is trying to kill them. Constantly. Endlessly. Hungrily.
And that, oh that, is the wonder/beauty/thrill of writing fantasy, because you get to make it up. But...in accordance with the rules of plausibility and believability. I sort of got lucky in Firedancer because the location of the main action allows the setting to be quite Earthlike, with certain vivid exceptions. But the next novel, Windrider, set in an entirely different part of this world, forced me to delve immediately into the intricacies of ecology and evolution required to sustain life here. What special protective traits would the plants and animals evolve? How would they survive the constant influx of fire or the killing winds and storms? What customs evolve designed to keep our human inhabitants from quickly becoming extinct? Studying earth critters only gets me so far. After that it's up to the imagination.
Fascinating stuff, worldbuilding. Beginners have no clue how important it is to understand not only what the trees look like, but what the coinage looks like and how food is produced and transported and how law and order functions. In short, they usually fail to construct any sort of believable world because they fail to look around at how our own functions and translate the necessary bits into their made-up universe. Form follows function in everything from the design of tools, furniture, and transport to the shape of a beast's horns. Thus is it with "making up" worlds as well. The more fantasy you write, the more you realize the devil is in the details, and those details are why a lot of readers tune in. Not to be hit in the face with them, but to fall easily and painlessly into a place that feels real even as they are escaping "reality."
I foresee much research coming my way, but it's all to the good! Lead me to those adaptive traits, those strange trees, those interesting houses. Every one of them helps shape my world, and thereby my characters who exist in that world and are adapted to it. Heh heh. It's not every day you get to play God, is it?