When Clay pushes the truck with the dead guy in it over the cliff, the truck eventually explodes in a huge fireball. But later, when we cut back to the police investigating the incident, the truck is not charred by fire at all.
When Clay is being interrogated for the first time, and he is asked if he was just friends with Amanda, he sits with nothing in his hands or mouth. When he answers "no" a second later, he has a cigarette in his mouth and matches in his hand.
In the Doc Holiday's bar, when Clay is playing pool (shortly before he slaps Amanda), she comes in wearing a red dress with straps. In the scenes, her left strap is first off of her shoulder, then is back on in the next shot, then back off her shoulder again, then off again, and then finally on.
The shot starts off with a full sized powdered donut being dipped into a red coffee mug thats obviously too small for the huge donut. Next shot is Clay's boss bringing a half-eaten donut to his mouth as Clay walks into the shop, apparently late again. He looks over his shoulder, and back to the donut. He then brings a large white styrofoam coffee cup into frame and dips the last bit of donut into it.