First scene at Steppes, when Sara and Derek are dancing, one of Nikki's friends is dancing next to them, then it cuts to her sitting with Nikki while they talk about Sara then cuts back to the dance floor where she is still dancing next to them.
When Sara first goes to the club, she is seen greeting Diggy and all their friends. In one of the next scenes in the club, on the same night, a break dancer is shown in the middle of a circle. Diggy is seen in the circle watching, with a completely different outfit on.
The first scene at Steppes has several shots of the dance floor that are from the final scene of the movie. You see Diggy in the pink pants and Nikkie in the black skirt as well as the individual dancers.
In the scene where Sarah breaks down about her mom and the accident after leaving the theater, Derek mentions Juiliiard before she does.
In the break-up, Sara, seated, has a sweat spot on her sweater. After walking across the room, the spot has disappeared.
There are several mistakes in the movie's depiction of Metra trains.
Obvious double when Derek is dancing and does the splits.
The same shot showing the school entrance and a guy wearing a yellow jacket walking on the street is used twice. Once in the scene where Sara arrives at the school for the first time, and once right before the scene with Malakai and a girl in the school bathroom.
During the shooting at the basketball court Derek's elbow pads are visible.
Given that Snooki is in a senior high school English class, he pronounces Truman Capote's last name as 'compote,' not 'Capote.'
When everyone goes to Steppes together for the first time, Chenille tells Sarah that her son Christopher's father is coming over to them. Her lips do not match her words.
During the ballet lessons, the class is dancing. Although you hear the teacher saying exactly which movements the students should make, you do not see her lips move at all. The given instructions are synced with the visuals.
Large set lighting piece visible twice in Sarah's bedroom. Once, beginning of movie when she first arrives in Chicago. Again, very noticeably, when her father reveals the redecorated room.
It's mentioned that Snookie was held back in school twice, 5th and 6th grades. But he's seen in the same English glass as Derek and Sarah, who are both seniors.
Juilliard is misspelled as "Julliard" on the sign announcing auditions.
Derek and Chenille are not convincing as brother and sister because they bear no resemblance to each other. Actor Sean Patrick Thomas's heritage is Guyanese, whereas Kerry Washington has American and Jamaican ancestry.