If your talking about like this then that takes a LOT of work. The short and simple way to explain it is, you have to outline the whole truck, lights, windows, wheels, grill, etc. by hand with the pen tool. Then you have to outline the highlights and shadows by hand, and after that you color it in.
Here is a tut. for photoshop if anyone wants it, not the best tut though.
Photoshop Tutorials - HV-Designs.co.uk