I was recently seeking an idea for a short story, and at a bit of a loss dug through my novel ideas. I came across one that was beautiful and I loved it, about mermaids in space. But for the purpose of the novel I needed something else, something different. So I went back in time, and found a much smaller voice in this world. What her story sounded like, and what it meant to see the world through her eyes.
It was different, and soft. I didn’t have the original idea’s woe and drama.
It was nicer to write.
But while I could appreciate the character and what that short story represented, it helped demonstrate the world building involved. A lot of the time in scifi, fantasy or even paranormal, we can have magic systems, or technology, that feels like its so far out of your scope its hard to nail down.
Short stories are an excellent way to do this, to build upon that world.
You can try this in many ways without undoing the initial idea.
Write a history like a university lecturer.
Tell a version of events like you would for a children’s book.
Share a memory of your main character’s best moment.
Lean into the villain’s path and how it will cross with the hero’s.
Find someone wholly removed from the story, and treat them as if they know nothing and are learning about this world, or if this is where your character starts, have them know everything and have to teach someone else.
Tell the parent’s story. The old wise woman when she was a girl. The cruel mentor before the world turned them.
Who hurt the love interest and made them jaded.
There are so many facets and even if those stories never see the light of day those people become realer and more familiar to you. As you get to know them, to write about them, these traits will be firmer in your mind. You will speak more confidently about them as people rather than figments of your imagination. This will give them behaviors and social patterns recognizable to the reader.
You may end up discovering that there is a whole world to explore, more than one short story or idea. Whole avenues to write a series into, to make worlds of stories.
What you do with these ideas, where they end up, can be some very different places. The most important part is that you are enjoying the time becoming more familiar with these ideas, developing not just them, but yourself as a writer.