Some good tips here at 7 Tips for Taking Better Photographs of Cars . Another tip is to avoid having the wheels turned toward the camera; best to turn them away a bit. In the right light, having the parking lights lit can also add some interest. Those glaring white dots of reflected light drive me nuts and are almost impossible to avoid. I walk a bit in each direction to see if I can minmize them. The pros actually use a dulling spray of some sort.
Nothing too great here, just a grab shot of my wife's '17 Wolfsburg 5M.