When Jake and Rosalie exit the motel from the interior, the door hinges from the right side. In the exterior shot, the door hinges from the opposite side.
When Jake leaves for the bank in the opening of the film, his headlights are off. In the next shot, they are on.
When Jake and Rosalita are staring across the border, the shot of downtown El Paso is played in reverse. This is obvious by looking at the people and the cars on the street below, moving backwards.
Reflection of camera visible in an extreme close-up of Jake's Eyes.
When Herman gets out of the car at the end of the movie, the boom mic can be seen reflected in the door's window.
The boom mic is reflected in the car door near the end of the film, when Herman gets out of the Cadillac.