When Jenna is driving the Mustang, a license plate is on the front of the vehicle. Pennsylvania DOT only requires a license plate on the rear of the vehicle.
When Ezra and Ella have the conversation about Emily the blackboard is smudged in one shot, whereas in the same scene the chalk is still clear and visible.
When Hanna and Aria are about to follow the taxi Jenna just entered, they put on their seat belts. When filming Aria doing this you can see a hand on the outside of the car window, possibly about to open the car door.