Characters interact with the setting as much as they do with the plot and other characters. In fact, setting can be used as another character, one that is implacable and without reason. Like a character, the setting can have scars, weaknesses, moods, even a personality.
The setting should be integral to the story. It needs to be more than a backdrop for or an introduction to the events. A static description adds nothing to the story’s purpose. The setting should not be any old place, but a unique place that has meaning for the character. Setting can work for or against the character, but either way, it must be dynamic, otherwise it’s just filling space.
Setting can create a mood. It can suggest the character’s motives. It can predestine character in the same way we are all creatures of our environment. A person who grew up in the shadow of mountains is different from someone born by the sea. A child living in a mansion is different from a child of the streets.
Setting can help move plot along. Whenever things slow down, the introduction of a real or perceived change in the setting can deepen the character’s conflicts. Maybe the character sees things he never noticed before; maybe those familiar things now seem menacing. Or perhaps the weather can take a disastrous turn.
Every description of a place should have a memorable quality that hints at the story’s meaning. In Story, Robert McKee wrote, “The irony of setting vs. story is this: the larger the world, the more diluted the knowledge of the writer, therefore the fewer his creative choices and the more clichéd the story. The smaller the world, the more complete the knowledge of the writer, therefore the greater his creative choices. Result: an original story without clichés.”