World building is an important part of any story. It is important to remember when writing a story that it's a world outside of the story and your characters. You can have many things but they have to have a logic connecting them together.
For example my story with Olivia and James and Vestina's Furry Rome have interspecies couples able to have children. For this we have the rule that the child could be either of the parents' species. I use that to describe their personalities and their children's. Yes I blatantly stole that part from her. She absolutely knows and is okay with it.
Which brings up a point that I don't see discussed often enough. You aren't going to make entirely new and original worlds. It's what you do with story elements that makes it unique. The world of Avatar (blue aliens) didn't invent the ideas of floating sky islands and a group of people having a powerful bond with animals/nature. I know of several different cultures that came up with those exact ideas independently. Even the word Avatar comes from the Hindu religion for how their gods interact with mankind through a physical body.
The other part of world building that you need to keep in mind is to have everything tied together. Don't add superfluous details to a story. A quote from a friend of mine when I was first trying to write a story that perfectly illustrates this. "That's an interesting geopolitical structure you made up. How does it relate to a dragon living alone in the mountains?" Yes the story was written from the perspective of a dragon living alone in a distant mountain range, far from the kingdoms I had described to my friend.
You can have all these interesting and fascinating things in the world you create. You just have to either leave it for your notes or reveal it as necessary. Otherwise it's going to feel disjointed and/or be a boring exposition dump.
As an example you can have these elements in the same story. Floating islands with cities on them, guilds that control much of the government and fight each other, a magic system dependent on magic crystals, and various monsters. You can tie them together by having the guilds control the crystals that the people use. Have the guilds' headquarters located on those floating islands and the crystals cause them to float. With the monsters being animals mutated by constant multi generational exposure to the crystals in close proximity.
As a final thing to remember about World building. You can't get every tiny little detail in your story. Much of The Silmarillian had been done before Tolkien ever started working on The Hobbit. Do you think most people would have read The Hobbit or Lord of the Rings if you had to read 100 pages of backstory on every single thing? Ofcourse they wouldn't. It's boring, tedious, and breaks up the flow of the story.
