Recently I mentioned making a mistake in marking my boards and transferring dovetail patterns as a result. A helpful reader has sent me a great idea for marking box or carcase components using "carpenter's triangles". I had already been using this type of mark when gluing up larger panels from component boards, but the clever part here is something I was not clever enough to think of: marking the box components on the top edge instead of on the faces. The top of the box is generally planed once assembly is complete, so the marks will come off. If this is a concern, you could always do this same thing on the bottom. This is perhaps not news to any of you experienced joiners, but I sure appreciate knowing about it. The reader says he learned this from Chris Schwarz.
The images tell the story better than I could, so here they are: