Dark when you paint the right way is
1-Lightly sand the surface where ur gonna paint with something like a 320grit
(the little grooves give the paint something to stick to)
2- light coat of Lacquer Primer (if you use enamel it takes a lot longer to dry and paint sticks better to primer than metal)
3-lightly sand the primer when dry (with 600-1000 what ever you have)
4-paint the color.
5- if you really want to go nutts, after the color Dries real good(a week with enamel or a few hours with Lacquer) sand it with 1000 to 1500 paper than spray clear over it.
Also dont forget CLEAN is important, no touching the surface with fingers (oil in skin)
And when I started painting my stuff was pretty bad, practice makes perfect in painting. I remember the first car I painted almost made me cry (it was that bad)