Continuity mistake: As Peggy comes to see Bobby about how his essay is going, there is a pad and pen next to him on the bed. The next shot Peggy sits down next to him which was where the pad and pen were on the bed. She then reaches for the pad and pen from behind Bobby. She never makes any movement before or after she sits down so there is no way she put the items would go to being behind Bobby.
Revealing mistake: Whilst Bobby is reversing the truck before hitting the flagpole in Bill's yard we see the driveway in front of the truck. The very next shot shows Peggy from behind the truck instructing him how far to go to the flag pole and you can see they have used the same background as the shot before from the other angle. You can tell this as both shots are the same background as both angles despite from different viewpoints are exactly the same items and objects in both shots. Added to this there is a driveway in each shot, and Bill doesn't have 2 driveways in his backyard.
Continuity mistake: When Bobby & Peggy are about to steal Bill's flag, the truck drives right up against the flagpole. In the next shot Bobby is standing next to the flagpole and there are a few changes. The first is that the truck has a bit of space between the back of it and the pole, whilst the first shot it had no space in between (as it hits the pole). The other change is where the rope is knotted on the pole. In the first shot it was on the opposite side of where Peggy was standing. The next shot she has not moved but the rope is right next to Peggy facing her.