One of the things that my boxing coaches have been working with me on is not thinking too much about "head" v. "body" but trying to consider my punches and target them more particularly. It is, admittedly, still a work in progress, but I've found that a lot of my work with the double-end bags have gone a long way to helping me think about it that way, as has more complex approaches to the mitts.
I like to bang on their gloves before I attack at a different level. Partially to mess with their balance and partially to mask the body punch.
I need to try aiming for more specific areas. I'm really guilty of aiming for the general target, and my accuracy suffers as a result of that sometimes.
I agree about banging on the gloves before going to the body, though one of the things that I'm working on is using the body shots off of some of the more dramatic slips, especially where my opponent over-extends with a cross or something like that. There are lots of ways of approaching the body, and one of the big things for me is just to stop thinking about the "body-punch" as necessarily a hook to the ribs, and understand it as something more multivalent, much like thinking about regions of the face, though with more focus on angle of entry of the punch. Anyway, it's just a thought.