How do you make a matt colour "look" shiny? I've clear coated but it just doesn't shine like it should.

Is it a genuine matte coat (ie a colour coat meant to be clear coated)?

Clear coats need to be sprayed on "wet" (one stop short of running) and that takes skill.
The paint has to be given time to flow to create a great shiny smooth surface off the gun.
Some pros mist on some pure thinners to help things along, but this has its own risks.

Try a paint polish?
If that doesn't work step up to a rubbing compound.
If you need something even stronger, 1500 or 2000 grit wet sandpaper.
Follow up with less aggressive steps.

Ok basically i painted my wing, the clear coat i used didn't stick to the paint (it was a diff brand). Then i put the wing on and it appeared darker, but the real difference was that the wing was matt, and the car was shiny. As far as i know the wing paint SHOULD be metallic, but looks matt. I clear coated the sides and a rough go over the top and edges, now in artificial light you cant tell the diff between the wing and body, but in sunlight at some angles you can, some angles you cant. I think i'll give it all agood polish, wash and wax etc. if that doesn't help i might try a couple more coats of clear coat. Thanks for the replies guys!