Most people think of fantasy and science fiction when they hear writers talk about world building. Writing good fantasy or science fiction requires a lot of thought to construct an original world with non-contradictory rules and limitations, but the truth is that every thing you write requires some world building.
If I were to write a story happening right now, right here as I sit at my computer, you would still need to “see” the world around me. Depending on the story, you might need a general idea of my surroundings. Is it rural or urban? Posh or run down? Winter or summer? The story determines which details the readers need to know, but no matter how familiar it may seem to the writer, the reader still needs information.
The first step in building a world is deciding what sets your world apart from other worlds. My story world is rural, and in August the white-tail deer regularly wander through the backyard searching the ground for apples. In someone else’s story, the people might go out on the porch, or sit on the stoop to escape the heat. In yet another story, everyone might be forced to live within a domed environment, breathing recycled air and rubbing up against their neighbors all too often in the cramped living space.
Once you have a clear and complete idea of the world, the next step is to determine how much of it needs to be shown to the reader. In a story set in my home, there are many details that the reader will fill in for himself without any prompting. All I have to do is mention a sweltering summer day, and the reader sets the stage with a yellow sun, blue sky and perhaps scattered fluffy white clouds. Green trees and grass would fill in the landscape automatically. I would only need to point out the specifics that pertain to the story—the half-dead spruce by the front door, or the stand of pine trees that shield the house from passers by. If the people from the domed environment stepped outside, the reader would need a lot more details to make a mental image. Color, wind, flat or hilly, rocky or sandy…maybe a huge red giant of a sun hangs in the sky.
You as an author need to know all the details, but only include the ones that pertain to your particular story.