Author has written 11 stories for Harry Potter.
I read a lot of FF, mostly Harry Potter, and there's a lot of common mistakes out there, xD. Some are just too funny when I see them, LOL.
Blaise Zabini is a BLACK MALE not a white female. It drives me crazy when people assume he is white, let alone that he's a girl.
Severus Snape is not sexy, nor would he make a good pairing with Hermione. Or anyone. Can we say ew?
No matter how good of an idea it may seem at the time, DumbledoreXStudent is not okay. Ever.
Pansy Parkinson is not a pretty blonde. She is an ugly pug faced girl with black hair.
Neville Longbottom is not a secret sex god.
Blaise does not spell his last name Zambini, nor does he spell it Zambani.
James Potter was never secretly gay with Sirius.
Nor was Harry.
You can go overboard with the Sirius/Serious jokes.
Filch threatening to hang students by their toes in the dungeons is not kinky.
No where in any of the books does it say that Dumbledore is fond of Lemon Drops.