Over the last few years, I’ve written tons of short stories! I started writing them soon after I had my first child. As a new mother, I found it difficult to get the focused, sustained time and attention I needed to write a full length novel, so instead I started writing something short. I ended up really liking short stories, both to read and to write, because they can pack such an emotional punch in such a quick period of time.
Short stories are also good way for writers to explore different genres or writing styles without committing to an intense project. If you normally write serious, dramatic novels, you could try writing something light-hearted or funny in a short story. I've written short stories about minor characters or aspects of a world I might later use in a novel. That allows me to flesh out these side characters and give them more depth, and it can help with world-building.
It can be tricky with science fiction or fantasy stories because often the worlds we create in speculative fiction are unique to our imaginations. This is why many fantasy writers spend so much time "world-building," or writing about the setting of their stories or novels. For short stories, our world-building needs to be economized as much as possible. We need to suggest the nature of our world in a few words, or else our "short story" quickly swells into a novel with a limited, short-story plot. I handle this by trying to keep the world entirely within one character's perspective. If that character knows little about the nature of magic or a scientific discovery, then I don't give the reader an explanation either. It's often more dramatic and emotional if characters don't completely understand what's happening to them, or how things work. Life is often bewildering.
While writing short stories is a fun challenge, reading them wonderful too! I love many short stories by writers such as Connie Willis and Neil Gaiman. I also like reading multi-author anthologies such as Black Swan, White Raven, edited by Ellen Datlow and Terri Windling, or the Nebula Awards Showcase books, which have some really excellent science fiction. Books like these can also help you find new authors whose writing and story telling you admire.
Of course, if you enjoy short stories, I hope you’ll read my book, Sapience, as well!