Basic building blocks of a story
A story, at its purest form, is a sequence of events. One thing leads to another, and another, and another. You feel like you start somewhere and end up somewhere else. There's a momentum, suspense. Things feel like they're going to happen and change. Thoughts and ideas -- emotional reactions from your characters -- can also be part of this sequence.
Moment of reflection. As a storyteller, you or one of your characters can at some point step back and reflect on the story and say why it's important, why you're bothering to tell it, and what the greater importance and significance is.
Dramatic questions. An important part of telling a story is raising a question from the beginning, a bait. Any question you're going to raise, you're going to answer, and the whole shape of the story is you throwing out questions along the way that your audience is going to try to answer and that you will answer.
Pacing. Some other helpful things that create a narrative arc and narrative tension lie in how you reveal the story and the pace of the unfolding narrative. Use silence as well as sound. Let the story breathe, let your audience breathe and absorb what you're showing them.
Show and don't tell. This is a visual medium. You don't have to explain everything.
Explore ambiguities and contradictions, if you can.
If you're making a short video, think about what advertisements do very effectively. Ads work for a number of reasons, such as appealing to impulsivity, self-gratification and desire, but they also do these things, which can easily modeled.