I'm not sure specifically as I don't know which 'the contest short story' you are referring to. It could be about a competition, perhaps a writing contest where the story itself is either the entry or about the experiences within the contest.
Well, for a YA short story contest, common requirements include a word count range, like 3,000 to 8,000 words. Also, the story might need to fit within a given genre or topic. And often, there are rules about originality and submission format.
First, have a clear understanding of the contest theme. Then, do extensive research if needed. Polish your writing, check for grammar errors, and make the story emotionally resonant with readers.
How about a world where everyone has to wear a device that monitors their thoughts? The slightest hint of dissent and they are immediately sent to 're - education' camps. The main character manages to find a way to disable the device and begins to spread the knowledge of how to do it, creating a subversive movement.
One idea could be a world where people are ranked by their genetic purity. The government controls every aspect of life, and those with 'imperfect' genes are relegated to slums and used for menial labor. The protagonist, a person with a hidden genetic defect, discovers a resistance movement aiming to overthrow this discriminatory regime.
In a dystopian short story, you could have a society where water is extremely scarce. The rich hoard all the clean water, and the poor are left to fight over the little that remains. The main character is a young girl who tries to find a hidden water source that is rumored to exist, facing many dangers along the way. It could show the extreme inequality and desperation in such a world.