Sand down the fiberglass until the finish is shiny and smooth. As you sand, gradually increase the sandpaper grit.
Clean the fiberglass with a warm water and soap solution. Ensure that you wash thoroughly, and afterward, rinse off the solution with clear water.
Select the top coat paint and get the matching primer base for the specific paint selected. The best choice for a top coat is acrylic paint.
Prime paint first and let dry. Optionally, you can sand with a 120-grit sandpaper.
Apply the top layer of paint. Usually, all it takes is one or two coats. To make the job go faster, you can utilize a paint roller.