After stain removal use 1000 grit wet or dry sand paper with plenty of water. Be careful not to sand through the gel coat. You should end with a dull oxidation free finish. Next use either rubbing or polishing compound. The choice depends on how dull the finish is.
You may have to start with rubbing then go to polishing compound. After the polishing compound there should be some signs of a shine. If you can lay your hands on a good buffer the polishing compound will give a shine. Next a wax/polish such as Turtle Wax. hit it hard with a buffer and you should have a good shine. In order to maintain the finish wax every six months or she will rapidly oxidize. Most people that are serious about appearance will paint. Good marine paint may last eight-ten years with out maintenance.
However good marine paint is expensive. $20-50.00 a quart. If you have gel coat with glitter (as above) just polish and wax every six months. Old boats is kinda my hobby. most of mine I just paint, however I don't have any with glitter.