The grammar, punctuation, everything like that is pretty much self explanatory. It needs to be there, or the story will be pretty much useless to anyone but the author. Unfortunately.
The thing that makes or breaks a story (in something else than preference, sissy/non sissy, whatever), is the setting. If the story is placed in a bubble, for instance at a school, in a nurses office, in a house, and it just never seems to leave or introduce new settings, it'll get old fast. Placing a story in a proper universe, be it sci-fi, alternative universe or pretty much just the one we live in is just so important to give a story life.
Additionally, the Mary-Janes get old fast. It's a bit like Twilight. You find a an author who has pretty much written how he/she WISHES he/she was like, their life, lovers, everything.