Since we did not read that story it will be impossible to make reference to that story! However, you can at least think about any writing and what makes it original.
Original characters, ideas, thoughts, emotions, the words, form, grammar, syntax, spelling, etc. Good writing will give the reader a sudden insight; it touches that reader in some way and they become involved with the story.
An original work would be copied or plagerized, would have tired coomparisons, clichés, etc.
That should give you SOME ideas!