The most powerful way to depict setting is with telling details that affect and influence characters in the same way as does plot. The technique adds unity by tying the setting to the story’s characters. They are not just in the setting; they are interacting with it. How characters respond emotionally to the setting allows readers to identify and empathize with them. We all know what it is like to enjoy or dislike a particular place. When writers have their characters tell what they feel, readers will, based on their own personal preferences, agree or disagree. Either way, their feelings are engaged.

You can develop a character by showing how he or she reacts to your setting and why. (Image: public domain.)
In some cases, characters may have been shaped by the setting in which they grew up. Such people tend to have unusually strong feelings about where they are now. Depending on whether their earlier experiences were good or bad, they may feel sadly out-of-place in, or happily prefer, their new surroundings. So consider your characters’ pasts when showing readers how (and why) they feel about their present surroundings. This is another way of tying the setting to the characters, another way of giving the story greater unity, cohesion, and depth.
As mentioned, plot also affects and influences characters, so if plot can be strongly tied in with the setting as well, one will have a neatly integrated story indeed. For instance, a fantasy story based on capturing a fortress would benefit hugely if the plot made use of particular details of the castle and its immediate surroundings.

Setting can make characters act. In the desert you must find water. (Image: public domain.)
Setting can influence characters to act. In a desert, people look for water. Setting can affect how characters feel. If you are an inmate, a dungeon can be a tad depressing. Setting itself can sometimes become a character and thereby act as a central part of the story played out within it. Think about the desert again. The water hole gone dry, the dust storm, the scorching days and chilling nights may all seem like hostile acts to people lost among the dunes.
It is important to know beforehand how much stress you need to place on setting. The key question is this: how setting-dependent is the story? The greater the dependency, the more prominent and well-defined the setting will have to be. Milieu stories, such as fantasy novels, always require a rich well-developed setting, and the characters in such stories should have a continuing interaction with that setting as well as with each other.
Settings must be vivid. They should not be just pallid backdrops. The reader should be able to feel, experience, and live them as the characters do. Here is where those telling details earn their keep. Remember that a few carefully-chosen particulars can define a setting more clearly than pages of vapid generalities. Imagine and describe what stands out.
Setting should count in the story; it should add to and enhance the story as it unfolds. Descriptions of setting should contribute to a work both emotionally and symbolically. You should achieve an effect by charging the language, selecting or omitting certain details, having the viewpoint character react in a particular way, and so on. Your goal is convincingly to immerse your readers in a milieu not normally their own. You must impress them.

Setting also affects the reader’s mood. Impact and impress your readers by deliberately working on their emotions. Make them feel something and they will remember you. (Image: public domain.)
Descriptive passages should do much more than just depict a place. They should reveal character by telling how various characters respond to their surroundings. They should foreshadow action by hinting at what a specific character might do in these circumstances. They should establish mood by using loaded words to manipulate the reader’s feelings. When approached in this way, setting contributes to all aspects of the story, thereby enhancing the whole.
Milieu novels – mostly science fiction and fantasy yarns – are a special case. They are unusually setting dependent. Scenes that have nothing to do with theme or character revelation are okay in such stories so long as they do develop or enhance the milieu. Be careful, though. Even the most rabid milieu fan still likes to see some story.
So put your best keyboard fingers on and get down to work depicting that setting.