Use a well-sharpened pencil to make cut marks for your shop projects. A blunt pencil, held vertical to the rule, will make a line too far away from the edge. Angle the pencil about 45 degrees to keep the line at the edge of the rule. For greater precision, make your cut marks with a utility knife using a sharp blade.
If you have dents in the metal-clad doors in your home, one answer is to use auto-body fillers to make the fix. Either the polyester resin or fiberglass paste fillers bond well with steel, and the repair can be made like on a car. But, because you can finish the door with acrylic-latex trim paint, not glossy auto body paint, you don’t need the skills of an auto body technician to get excellent results.