1. Background
Find a background that is not too distracting, such as too many other cars or people. The viewer will have a difficult time knowing where to focus. Usually a nice scenic background works well. Such as the beach, horizon, rolling mountains, rocks, winding road....well you get the idea.
2. Angles
Try lots of different angles to achieve your goal. An extreme angle can be aggressive where as a straight-on shot may be more simple.
A good rule is start off with a good eye-level. This makes the car look appealable and accessible. High angles can natural make the car look smaller, and usually this is not the image that we want. Try tilting the camera making the car appear as though its driving off, giving it motion, suggesting speed. Too extreme, however, may force the viewer to tilt their head too much and can be distracting.
One of the easiest angles to achieve is ground level. This is what a lot of the auto magazines use. Remember to get a shot of 360 degrees of the vehicle: hood, front, rear, sides, wheels, etc.
3. Panning
Panning is a little more advanced but can be mastered with a little practice. I suggest using a tripod, but a steady hand with work too. The results are a blurred background, blurred wheels--giving the feeling that the car is speeding away. Generally, set your shutter speed no faster than 1/125 and an F stop of F8 or higher. Follow the car while snapping pictures the whole time--this will increase your odds of getting that wining shot.
4. Moving Vehicle Shot
For an even more advanced technique try shooting the car from another moving vehicle..just use caution!
5. Lighting
There is nothing tackier than a nice photo of a car with the shadow of the photographer in the foreground. Fix this by shooting with the sun behind you.
6. Zoommmmm...
Zoom in and make the car take almost the entire area. Very dramatic.
