After the Snowman head falls on the Doctor, the TARDIS changes position down the street. When he points it out to the police officer, it is clearly visible from their position down the street, but when he enters it, it is now positioned behind a corner wall.
After Ruby gets the phone call from Davina McCall, she is heard putting her phone down on the counter by the baby monitor. In the close up shot of the baby monitor the phone is not there. In the reverse shot after that the phone is on the counter, near the baby monitor.
When the TARDIS is parked on the sidewalk in front of the houses, it is standing next to the red car. Then, in a later close up shot, it's partially behind the red car, then it goes back to a wide shot and it's next to the red car again.
When moving through the ventilation system of the goblin ship, Ruby clearly rips the knees out of her tights. In each following shot her tights are clean and good as new.