HELP! Polish paint before or after clear coat?

I’m new to modelling, so please forgive me if my questions are stupid. I’m building a 1/20 Tamiya
Mclaren MP4/8 F1 car, and I’ve painted the white and red color scheme on the body parts. Do I fine
sand and polish the parts before I paint the clear coat, or after, or both? I’m planning to airbrush
Model Masters clear laquer over it. And what ratio do I thin the clear laquer to? And should I clear
coat over the carbon-fiber decals I’ve put on the chassis parts? Thanks for any help you can offer.

Don’t bother with MM clear lacquer, it is too thin, and you would need too many coats. If you are going to clearcoat, use Testors gloss enamel. However, on solid colore, I usually just polish the paint. On metallics, like metal flake paints, etc, I will clearcoat and then polish, as polishing them will spead the flakes around, which is not good. I know, been ther, done that, bought the tee-shirt. Hope this helps. E-mail me if you need further clarification.
Lee