My way of doing it anyway. Others may agree or disagree given what they find to be easier, but to anyone wanting to get started this is what worked best for me. I had plenty of practice on my 650 cases and I find myself occasionally polishing a tool, brass key or whatever just because I like shiny! The following pics are a current project and polishing takes up gaps and bad weather delay's. Something that is happening quite frequently lately. I start out cleaning the piece with 4x steel wool to remove any loose clear coat and oxidation.
Then I hit the piece with as high a grit as I can get away with to remove any remaining clear coat or deep scratches. In this case I started with 400g. Just don't sand too hard or you create scratches. then I refine with 1000g and finish with 2000g. I start polishing with black polish stick to pull any final scratches out and finish next with an Emery stick. That will usually do the trick unless you want to take it one more step and do a high polish with green stick. (I usually do). The results speak for themselves and as I said, it's a great fill-in to work on while you're waiting for another part.