Novels have much more space than short stories, which gives you more leeway with the number of characters you can include. Even 'furniture' characters can be described and given speaking parts to develop background or atmosphere.
Before the scene, before the paragraph, even before the sentence, comes the word. Individual words and phrases are the building blocks of fiction, the genes that generate everything else. Use the right words, and your fiction can blossom. The French have a phrase for it - le mot juste - the exact right word in the exact right position.
For the professional writer, stories must be presented as a series of individual scenes, each one dramatized with dialogue and telling descriptions of who is present and what they're all doing.
A brief short story may require only a few paragraphs after the climax. On the other hand, in his massive novel 'The World According to Garp,' John Irving's denouement consisted of 10 separate sections, each devoted to an individual character's fate and each almost a story in itself.
The truth is, you have about three paragraphs in a short story, three pages in a novel, to capture that editor's attention enough for her to finish your story.
Words that add no new information or aren't repeated for emphasis are just padding. A sentence may carry three or five or eight of them, each one as unnoticeable as an extra two ounces on your hips but collectively adding up to a large burden of fat.