Depending on how much you want to cut will determin the paper corseness. I start with 1500 and finish with 3000 if needed. Add a little dish soap to the water in a 5 gallon bucket. Soak some 1500 wet dry paper for about 30 min., this make the paper easier to work with. Get your self a rubber sanding block and start with some small areas untill you get the hang of it. It's not a bad idea to tape off the edges with some 3/8 masking tape so you dont burn through.
Is this the metallic green one Evil?
As stated above, this depends on if its clear coated.