There are some tips I've heard over the last two years though:
Have 1 or 2 main characters
Focus on a concept of belonging. (e.g. A connection to others develops a sense of belonging. A connection to the wider world is important for a sense of belonging. Belonging can create barriers between groups. etc.)
Relate the story to something you know. (Stories in fantastical settings are usually inspired by hollywood, anime, soap operas etc. and therefore cliche. Also, sci-fi and fantasy stories generally take too long to establish the setting. Subjects like death and grief should be avoided because its unlikely that a 16 - 18 year old student can express serious themes like these properly with pen and paper.)
Make the story actually progress somewhere. Don't get carried away with description.