In the scene where the girls open the trunk of Courtney's car we can see that Liz is almost completely covered in bruises and her skin is pale, almost white. But as they walk through the pool area and up the stairs you can clearly see that suddenly her skin tone/bruises are completely gone. When they throw her on the bed suddenly the makeup and bruises are back.
When the newly-created Vylette walks into the school hallway for the first time, we clearly see her wearing a pair of coral-colored high-heeled pumps. The shot of her entering the cafeteria however clearly shows her wearing red low-heeled scuffs, then when she's seated the high-heeled pumps are back.
When Courtney is interrogating Fern in Liz's house, Julie offers to take Fern home, but Courtney stops her. Julie runs into Courtney's arm, knocking her sweater strap off her shoulder and revealing her bra strap. In the very next shot, Julie's sweater strap is back in place.
When Liz's parents return home and open the front door, if you look in the background you can clearly see that it does not match with a "real outside setting" for the neighborhood. The background is very bright and blue.