More pix of her plz
Turn wheels proper direction
Think about how you want the shots to turn out before you shoot
Adjusting your vantage point always helps
Your pictures are very cluttered, lots of stuff that draggs my eye away from the cars
Don't always go by the internal light meter on the camera. For the above picture in this post. Its "properly" exposed but if you were to over expose it a bit then the shadow on the rear of the red rice rocket would be more lit up. (Can also be done post processing, but easier/better to do it while shooting)
Shoot in RAW
This is the best shot of the bunch, IMHO. It follows all the rules, however i would have choose a shallower depth of field to draw the views attention back to the cars. Also would have underexposed it a stop or two to keep the whites white and not so blown out. Setting a custom white balance helps alot too, it appears that whatever white balance you have is working nicely here. (auto?)
Practice the "rule of thirds" more.
Seriously, more pics of the chick please.