A major yet intangible element of the story world, whether real or imagined, is the overall atmosphere you’re trying to convey to the reader. This is as important as the tangible worldbuilding elements because it sets some parameters for the rest of your efforts—what details to include and how to portray them.
So, when you write your story, what moods are you trying to present? Utopian or dystopian, free or restricted, hopeful or oppressive, safe or perilous, realistic or whimsical or surreal, familiar and cozy or foreign and unsettling?
First and foremost, what do you want the reader to feel about the story world? We are, after all, talking about a critical element of the reader’s experience of your story, which in turn is the whole reason for writing the story in the first place.
But it’s just as important to picture the world from the characters’ perspectives. Their view may be similar to the reader’s experience, but not always. If you’re writing from a first or close third point of view, the moods are likely to coincide because your reader is experiencing the world directly through their eyes. But if you have more narrative distance then there may be significant differences. For example, you may be portraying a world that your reader will feel distinctly uncomfortable with, but which the characters happily accept, or vice-versa.
To complicate matters, the exact same setting may affect different characters in very different ways depending on their point of view. So ask yourself how does each character inhabit your world? Their perspective will color their thoughts, words, and actions. For example, a Black person’s experience of life in 1950s Alabama will differ greatly from that of a White person. Ditto steelworker versus aristocrat in early 20th century northern England, or schoolgirl versus adult man in contemporary Afghanistan …
Understanding the atmosphere you are trying for is like choosing suitable lighting to enhance the scenery on a stage. The same props are there, but their appearance is dramatically altered by the lighting you choose.
Ian S. Bott, Writer and artist 