When Dexter is looking at Travis' drivers license his birth date is listed as November 24, 1977 and the issue date on the picture says September 23, 1990. That would make Travis 12 at the time of issue. Also below in the typed portion the issue date is listed as October 12, 2006.
When Dexter first sees "Apocalypse Bound" on Travis' bookshelf it is the 3rd book from the right end of the shelf. The action cuts to an overhead shot of Dexter removing it from the shelf and it has moved to the 5th from the left. When he replaces it on the shelf, the gap has moved to the original position, 3rd from right.
Near the middle, when Dexter searches Travis's house, he looks for the Appocalypse book on the shelf. The book is initially lying with a blue-spined book. Later Dexter is shown to be picking up the book and the blue spine is far away. He places the book adjacent to the blue spined book where there was no space earlier.
When Dexter runs into Sam in the police station, Dexter has his bag on his shoulder in the first shot, but when the camera cuts, it's gone. The shoulder strap reappears and disappears multiple times throughout their conversation and is ultimately back on when the scene ends.
When Dexter and Anderson are lifting up the body of the woman who shot herself, the entire floor around her and her chest is completely covered with blood, yet the gun under her body is almost completely clean.