Continuity mistake: Adam hands Katherine the note he found on the floor written by her aunt in a previous episode. Katherine is holding the paper up. When Adam walks around her in the next shot, the paper is gone and Katherine is only holding her keys/purse. The close up of Katherine (the very next shot) shows her holding the paper again.
Continuity mistake: When Orson is on the phone with his lawyer, he sets down the notepad with a page half filled with writing at the front. However, later in the scene Edie walks into the room and the front page of the notepad is full of writing, plus there's an extra line in the first paragraph. No one was around to move the page as Orson was in the shower.