Basic layer styles will do most of the time and finding a slightly scratchy texture for the metal shouldn't be too hard, either. This really isn't a question of "What?" but rather "How?" in the sense that it will simply take a bit of experimentation and finetuning to make it look good, be that defining the depth of a Bevel or playing around with gradient and pattern overlays for shading effects and a worn look.
Mylenium