In the diner, Harold holds a knife in his right hand, then a sandwich, then a napkin, then the sandwich again. Bad splicing.
Parents were called to the school over Amy yelling at the new student over a locker, but not when Colin previously destroyed the office of the basketball coach.
Ouija boards are not used in Chinese Medicine. They were meant to be a means by which to communicate with spirits of the dead. An early precursor was actually banned in China.
Story is unrealistic by showing Amy now as part of the swim team when previously she was running track, singing in choir, dancing in school ballet and performing cheers during basketball halftime. Electives require time, dedication and rehearsals, none of which Amy chooses to handle. Even if she did, having that many in one school year is not possible.