When Cinderella and her fairy godmother are in the pumpkin going to the ball at the end of "Impossible/It's Possible," watch Whitney Houston's mouth. There's one point where she's singing and her jaw is moving as if there is vibrato in the note, but if you listen to the note, it's a straight tone.
When the Prince and Lionel are testing the glass slipper on all the women in town, the scene shows a long line of feet waiting, followed by a few feet trying on the shoe. The final foot before the prince leaves the house frustrated appears to be a man's foot as it is much larger and the legs of the person are not shaved. The man is also wearing a white flip-flop on his other foot which is again uncharacteristic of all the costumes in the movie.
During the scene in the palace hallway, the Prince and Lionel are talking while Lionel helps the Prince get dressed. When the Prince goes through the passage to the room his parents are in, it's obvious he is not dressed well, with only two shirt buttons done up, cuffs undone, shirt untucked, etc. But when he meets his parents, he is perfectly dressed and neat.
When Cinderella and the Prince are singing in the marketplace, after the boxes get trampled by the royal carriages, the purple hat box changes positions. In the next scene from the back, the purple box is hanging in Cinderella's hand, and then the next shot it is perfectly intact sitting on top of the rest of the boxes. The box's placement changes a couple more times.