Pre-mix straight to the gun stuff is superb. I can't remember the name but it comes in a blue and grey bottle. The same rules apply as when painting. Make sure the angles are correct and there's not dust or moisture in the air or surface.
Depending on the quality of finish you're after you need to spend 80% of the time preparing the panel for paint. Etch primer, filler, blocking, sanding, hi-coat primer, sanding, more filling and sanding if necessary, more primer.
At this point leave it overnight.
A few coats of base color.
Again; you can apply lacquer half an hour after the colour is put down but I'd leave it a good few hours at least to ensure all the solvent has evaporated and pigment dust is out of the atmosphere.
Dust over with a dry clean cloth gently and finally apply the lacquer. It will go on a bit quicker than the colour but don't panic and whatever you do, take your time. Too much lacquer can ruin the base coat.
Have fun.