it helps to not have the food in the house that you usually crave (or get it out of the house, or hidden if possible). I've been craving my old comfort buddy ...a bag of chips and dip for a couple of weeks now.... but since it's not in the house I can skip it. When in the store I just tell myself the money is better spent on some veggies or 'real' food.
I don't crave something specific at night. I just want to eat anything and everything (though I could narrow it down to hot chewable things, I don't want cold food or hot beverages.)