hey matey, just replied!
Here is the pic i mention in the message. It is a rocker cover for a holden V8 that i did when i was just teaching myself how to paint. I stripped it back to metal, then primed and based it in black before marbling woth metallic silver. The skulls are more realistic than stylised, but the same principles can be applied to the buildup of the stenciled ones. The shading and highlight areas give depth and detail, making the finished product much more appealing in the end. These ones i actually drew on paper and cut out the same way you would use store-bought stencils, and from looking at real skull pics online i got the shading details. They were painted just using a white base, with transparent black to gradually build up the tones. Then the whole thing was coated in a couple of layers of candy yellow, and another couple layers of a candy yellow/orange mix, then cleared.
Anyhow, keep up the practice bud!

every man needs a shed, to put his stuff and clear his head and work out what the hell she said.