Sand it to 2000 grit or better (I go to 2500) then light buff with green compound followed with light buff with pink. It will look like glass! Be very careful not to overheat it, it can shrink.
Bob
ETA- Also, if you don't want that glass look, sand to 2000 grit and then rub it out with a gray Scotch-Brite pad. I get a very nice satin finish this way.