I have written a number of short stories, most way back in the 1960s and 1970s. If you look up my Hub Korean Christmas you will find one of them. It once won me 2nd prize in a competition so it must have something going for it.
With the short story, prune every unessential word. If it doesn't add something important to the setting, a character, or the plot, leave it out. And have the climax come right at the end. In the story I mention here it comes in the final sentence.
Use short, simple words wherever possible. Read Ernest Hemingway's The Old Man and the Sea and note the short, punchy, single-syllable wordage. He was truly masterful in that particular story - and goodluck.