Ok I can work with that. I'm the unofficial official east side photog for my car club so I've done this much. Here is a quick list to think about.
1. tire angle is key. look at your favorite shots and take note of the angles and what is achieved by using different angles. it is best explained visually.
2. placement is not always everything. move about and don't be afraid to climb on stuff or lay on the ground. always keep in mind the relative position of your light source(s) though. this is sometimes harder to manipulate without moving the vehicle.
3. time of day. night = tripod even if you think you can use a super fast prime and hand hold, you can't. dawn = fog you never know when that stuff will creep up on a perfect shot and fuzz it all up. you can often get cool back light shots in the am however. dusk = capital great coloring, great reflections and a great backdrop.
4. stay out of the shot. your shadow ruins it and so does your reflection in the vehicle.
5. detail sells it. people rarely oooooooh and aaaaaaaah over a shot that lacks detail in either shadow or highlight. some look cool, but often they aren't as well received as a shot that falls well in the dynamic range of your sensor/film.
6. HDR (High Dynamic Range). automotive photography is one of the areas in photography where HDR is a truly useful tool and not just a toy. [don't flame this please, it has it's place and it's awesome and blah blah blah except it's becoming a crutch for creativity and skill to lean on]{you know it's true}
7. I don't know anymore, beer me again.
8. oh yeah backgrounds.
A. parking strutures are sweet, but look for one that has all the same type of light so your white balance isn't the suck. they are usually empty and free at 4am. don't be afraid to move the trash can.
B. bridges. get under em. go nuts at dusk and get as many shots and positions in before the light fades. night shots can be cool if the bridge is really well lit or if it isn't, do a long a$$ exposure. in fact do a long exposure anyway.
C. fields. harsh shadows in the middle of the day. try messing with an open field on a partially cloudy day from a long ways off and preferably up high.
D. urban. look for grafitti. lather, rinse and repeat.
E. driveways. avoid em.
9. circular polarizers. get one and have some fun. they cut the glare on windows nicely, but if the front of your lens rotates while focusing it will constantly be messing up the filter position.
10. go shoot. really, right now or soon. screw up and learn from it.