When Julie finds out about Susan and Karl sleeping together, the tightness of Susan's dressing gown changes several times throughout the scene.
When Danielle asks Matthew out, she goes over to a lawn chair with a towel laying on it. As she is walking to the chair, the towel is smooth, but when she leans down to smooth it out, the towel suddenly falls several inches down the chair.
When Gaby goes outside to ask for help with her dress, you can see that the door is open when she leaves, but a couple of shots later the door is closed, despite Gaby not being near it.
Right at the beginning of the episode, we see a woman drop her daughter off at a strangers house. When the front door opens, a camera crew is reflected in the brass door knocker.