Don’t start writing a short story with a page count in mind.
Today’s tip may seem obvious to some people, but judging by the number of times I have seen it come up in writer’s groups and writing classes, I think it bears mentioning. A short story should be as long as it needs to be. Your story may take 1,000 words to tell or it may take 5,000 words. Either way, it will take as long as it takes. You may have an expectation of how long a story will be, just because you know what you plan to write, but don’t set out to make the story that length — just write the story.
There may be situations in which length is a factor. If you are in a writing class, for example, and your teacher tells you to write a 10 to 12 page story, you may be stuck with that limitation. I would question that instructor if I were in the class, but if the instructor was adamant; I would do my best to make it work. The first thing I would do, however, is write the story my way, taking as long as I needed. I would worry about editing it to their requirements only after I had first edited it to my satisfaction.
I once took part in a writing workshop in which one of the participants submitted a seven page story that had eight characters and five different settings. It was a whirlwind of events with little or no explanation or reflection. It was, in short, a cluttered mess. In defending her story, the writer said that she had kept it short, “because people keep telling me my stories are too long.” The problem was that this wasn’t a story that could be told in seven pages. At twice the length it would probably have still been too short to include all of the things that were going on. She didn’t really write a seven page story, she wrote a thirty page story in seven pages, and it didn’t work.
The opposite problem can occur as well, though it is generally not as serious an issue. If you had a perfectly good eight page story that you needed to “pad” to ten pages in order to meet a requirement, you might find yourself putting in or leaving in a few details that you would otherwise want to eliminate. My advice in that situation is to look for the most meaningful way to expand your story. You might even manage to improve it. If you don’t, you can always go back to your preferred version once the assignment is finished.