Repainting a side mirror and other bodywork

Hi!

I just changed the cover on my left rear view mirror and thus had to repaint it. I bought a set of spraycans from my Pug-dealer, vert mayerling it is called, a metallic green. Now I resprayed it with four or five coatings of green and one or two clear ones. Same with a spot where I filled a rust hole.

Now the color is really flat, not shiny like the rest of the car. Should I polish it and how do I do that or how do I get it to shine?

Thx for any help, Tobi