Thank you, NeeDeon. I'm flattered. It's the first time I vectorized a car, and it was not easy at all. I'm glad this one came out OK.
It's small stuff compared with the master car vectorizers here. The top one would be Ron "Knightedduke". His vector car collection is the standard against all is measured with here. You would want to examine the wireframes he posts, as it generally reveals how things are arranged.
No big secret, really. Just obsession with details. First block out the general shapes, then add details, finally work in the reflections and shadows. Hide parts you're not working with so it wouldn't get too distracting when working with the details. And learn to save the file and quit when your interest in it starts to wane. Otherwise, you'll probably get careless and ruin your work. At least that's what I do.
An example of Ron's work:
http://www.talkgraphics.com/showthread.php?t=2318