Get into your characters’ heads as quickly as you can. Can you sum up their main characteristic in one or two words? Can you sum up your story in a line or two? Are your characters different so you can tell them apart? Do their voices sound different so nobody is confused as to who speaks?
Moments of weakness in a character can be used to strengthen their portrayal. We all have moments like this - fictional characters should reflect that. It is then what real and fictional people do after having such moments that can add or make a story.
Proverbs are a good source of basic plot ideas which can be expanded out.
Look at what your characters have to gain or lose. Is that motivation strong enough for the plot you’ve got in mind?
Raise your characters’ problems, ambitions, ensure there is enough tension in your story. You do want to make a drama out of a crisis! (Without overdoing it of course!)
Consider politics! Whatever your fictional world, it will come into play. How does it affect the ruling classes? The peasants? How did the politics come about? Is there gender equality? Freedom of belief and/or speech? Are broadcasters, journalists or their equivalent free to report as they like or are they subject to controls and who operates those?
Since seriously trying to write short stories as well as the Brenebourne series, I’ve tended to type directly on to the computer. I have found it helpful to run my short story out on paper just before I think it’s ready to go as I’ve picked up errors that way which I missed when going through the same thing on screen. I don’t know why it’s sometimes easier to see things on paper than on screen but my experience tells me it just is!
The nice thing about short stories is you finish them relatively quickly, you can get them out there, always have something on the go or out there and if you do have any successes it’s useful stuff to put on your writing CV. Writing short stories as well as the novels has made me feel more like a proper writer as I’m submitting work more regularly. I also hope it’ll have a knock on positive effect on the novels too!