Unless you are highly experienced from working in the copywriting field, take a course. There are online courses or classes at community colleges and universities that can give you a leg up in getting savvy at writing copy for brochures, catalogs, advertising and, of course, marketing copy for the web. Before you do that, you need to know what those services will be.
You need to be able to heat the metal to manipulate it, and you need metalworking tools to cut and engrave it. But there are many other materials that you can work with to make jewelry–glass, plastic, …