"If a writer of prose knows enough about what he is writing about he may omit things that he knows and the reader, if the writer is writing truly enough, will have a feeling of those things as strongly as though the writer had stated them. The dignity of movement of the iceberg is due to only one-eighth of it being above water."This is why Hemingway made his stories so short. They are like icebergs, with a lot going on underneath the surface. He revised his stories rigorously, making them tighter and yet more suggestive with each revision. He packed a lot of meaning into a small amount of words. Read "A Very Short Story" by Ernest Hemingway, and you'll see what I mean.
I have always felt that Hemingway was a better short story writer than novelist. His short fiction is so strong, but it seemed like the longer form of the novel was hard for him. There's a quote from "A Moveable Feast", his great book about being a young writer in Paris, where he says he had worked so hard on learning how to write taut, condensed stories that writing a novel seemed like an impossible task. He couldn't imagine himself writing something that long.
Whatever you think about his novels, he is one of the great short story writers in English. You can learn a lot about writing from reading his short story collections.
And following his iceberg theory.