You're on the right track, cleaning and removing oxidation are good steps. The next thing you want to do to develop a good shine is to make the surface smooth.
Look at those incidental angles and observe for scratches on the surface. If you have the typical "swirl" or minute scratches, you can proceed two ways. First is to fill the scratches with a polish or sealant/wax. The other way is to gently remove material so the scratches are no more. This is usually done with rubbing compounds and a buffer.
I'd try this: At an auto paint store, buy some 3M Extra Fine rubbing compound. There are also "swirl removers" that are about the same light particle size. Buff out the fiberglass with the rubbing compound. Rinse and clean. Apply a synthetic acrylic sealer. I'm sure there are Marine varieties but I'm using an old can of Protect-all acrylic finish. Anything acrylic is what you want. Apply it and lightly buff with a finishing bonnet. Observe the shine. If you want more/deeper shine, apply a Carnauba wax and buff. You can keep applying wax and buff until it's ready for the showroom but a single coat over acrylic is going to be 98% there.
Good luck with the shining!