Welcome to my favorite part of writing, World Building.
In Science Fiction and Fantasy the world building is huge part of the novel. In Science Fiction the master of world building, using what we know about the universe, is Arthur C. Clarke. In his book 2010 he took the data from the Voyager mission that showed how Jupiter's moons weren't just lumps of dead rocks but vibrant worlds in their own right to create a fascinating, and possible, place where life exists on Europa and Jupiter's core is a diamond the size of Earth.
In Fantasy world building the master has to be George Lucas. In making STAR WARS he blended the pure Fantasy elements of many species living side by side and the space opera elements of droids and faster than light warships to make a fantastic fantasy place.
There is a lot of talk about how world-building is out in literature. I have four things to say about that:
2010 by Arthur C. Clarke, first novel to receive a million dollar advance.
STAR WARS by George Lucas grossed three quarters of a billion dollars.
The STAR TREK franchise turned Paramount, later Viacom into a media empire.
Lord of the Ring trilogy made over $2.5 billion.
I picked these examples because the world building in these stories overwhelms the other elements and they are hugely popular.
So how do you make a fantastic world to put your story in? Think about the elements of your world and what that does to the bigger picture.
In THE SETTING EARTH I placed the story on Ceres, the dwarf planet in the asteroid belt. I looked up a few facts about the place.
It's gravity is 1/38th that of Earth, so a normal person would weigh between 4 and 5 pounds.
It is roughly 100 degrees warmer than the space around it, where does that heat come from? Very likely as it interacts with other asteroids in the belt its core is twisted and turned making it volcanically active. What does that mean for my settlers on the Dwarf Planet? It means there could be an underground ocean and speculating further that ocean could contain native life.
Once I had that concept I could imagine all the fun that my settlers could do to transform this dwarf world into paradise.
A fun sport on the surface of Ceres would be golf. Under the low gravity even an amateur could hit a 3 to 4 mile line drive.
With the underground ocean they could build giant tubes 60 to 90 kilometers across and they could build a habitat larger than the horizon so you wouldn't be able to tell you weren't in a park on Earth except for the gravity. That difference is where they can have fun.
Weighing only 5 pounds and being in a full atmosphere of pressure, they could strap on a pair of wings and fly where ever they felt like going.
Other fun things about the world I created on Ceres. The day is 8 hours long, so besides a work day being a full day, its spin is faster than Earth. I had my characters rest by a waterfall and the combination of the faster spin and the lower gravity made the coriolis effect noticeable so the waterfall curved 40 feet instead of falling straight down.
Unfortunately I had to ignore a known unknown. It is very likely that Ceres has a few moons. I had my main character star gaze a bit. He didn't notice the moons because I have no way of knowing their size and orbit. The odds of my guessing right are slim to nonexistent so in 2015 when the Dawn spacecraft visits Ceres anything I wrote about Ceres moons would be proven so wrong that it would be a distraction.
What I loved about my building a world out of the little data we have about Ceres is I could let my imagination run free but it was bounded by a few guidelines to make it consistent.
In fantasy the same rules apply but you have to make your own starting points.
In non SFF world building is still important. Even if you base your story on a real place you need to decide what elements of reality you are going to use and what elements need to be replaced with fiction.
One author that is considered great at weaving fictional characters and events into real places and events is James A. Michener. Reading a Michener novel is an undertaking so pick carefully. His novels are finely crafted to have the story weave in and out of the real world. While reading his novels you do get immersed in the worlds he is creating, unfortunately they tend to run over 1,000 pages so even a quick reader like myself needs to be immersed in that world for at least a week. Unlike books from some more superficial writers that run that long, you can't read a few hundred pages put it aside for a week and start reading again.
If you like torturing yourself for your art, reading Michener is good for seeing the technique of combining the real world with a world he created. But I beg of you, if you do study his technique, make your novels shorter.
The final word of advice I have on world building is do the exact opposite of what is being said. In building your world be as imaginative as possible, as long as it stays within the guidelines you first set down. Clarke took everything we knew about Jupiter's system of moons and let his imagination run wild in creating the details.
Lucas took whatever elements he liked from any genre and mashed them together and forever changed SFF. People can argue if this is good or bad but it can't be denied that he changed the genres.
STAR TREK has become a genre of its own.
The problem of world building in novels isn't that people aren't interested in it. The problem is that writers have gotten timid and don't take the world building far enough.