Spider-Man faces forward to shoot webbing onto three staff-wielding warriors lying on the floor close together. Seconds before that, the warriors had been knocked down by Spider-Man apart from each other, with only one lying completely in front of him.
In the scene where peter falls asleep studying for his exams, his arm is behind his head. However, when he starts dreaming, both his arms are on his chest.
When J. Jonah Jameson looks back at Peter and says "Aren't you playing Hooky? Thanks for coming in." Robbie first turns to face Peter. In the next scene he's looking down at his paper.
When Peter is climbing around his Aunt May's house, it's obvious he's climbing on a giant picture of the house, because in scenes where he climbs down poles, his hands don't grip them.
When Spider-Man climbs to the top and hops on the roof and looks around, it's the same shot used three times.
When Spider-Man is fighting the three staff wielding warriors and he jumps onto the ceiling, the harness under his costume and the track on the ceiling that it's attached to are clearly noticeable.