Using a broiler without burning the top before the center warms through

My oven's broiler gives lovely color to cheese and vegetables, but the surface can scorch while the middle is still lukewarm. I'm trying to use it as a finishing step after cooking most of the dish through, rather than as a shortcut for the whole process. How far from the element do you place a casserole, and when do you switch between broiling and ordinary baking? I don't trust recipes that just say ‘broil until golden.’