When Miley and Lily are brushing their hair and talking to Roxy, there is a potato chip bag in front of them. Then when Roxy shows them her trick the potato chip bag is not there anymore.
When Roxy is showing Miley and Lily the trick with the pineapple in the kitchen, you can see the strings attached to the pineapple that make it split apart
Lily says that she and Miley are in high school, but the outside of the school says it's a middle school.