When Hannah first comes on the stage, she has a black microphone with a silver tip, but when she's singing, she has a black microphone with a black tip.
When Lily knocks Oliver's soda out of his hand, the soda cup is very clearly empty.
When Hannah is singing, the venue doesn't match the one in which Josh is sitting at. You can see the red chairs when they sit, but when the camera pans around while she sings, the seats can't be seen. Also, when Hannah was singing, the stage is different from the stage she talks on. This proves that her performance scenes were edited and instead, they put in performances from an actual Hannah concert.
When Jackson is trying on the sunglasses at the beach, you can clearly see the large blue filming screens reflecting in the lens of them.
You can clearly see a camera man while Miley leaves to get a pretzel.