When Jason describes his girlfriend Mary Jane to Julie and insists that she should meet her, while leaving the house Julie's white scarf is tied in one scene and untied in the next scene.
In the final scene, when Jason leaves Julie's house, she is wearing a black v-neck sweater and her hair is nicely coiffed. After she asked him to leave, when he decided to go back and try again, she is wearing a completely different outfit and her hair is longer and messy.