Choosing the right Scape to suit the style of car first, and if it doesn't look right by eye on the screen, try another similar Scape for the composition you are after. Try to move the car around the Scape even moving the car really far away and then don't be afraid to then zoom in to find the right lighting and shadows under the car. Reduce Aperture (blur) of the background 1.4 (full blur) if needed as it will make the biggest difference (Not in all cases). Use effects carefully and mask the car in the effects menu, then reduce the highlight and filters of the background individually trying each setting if needed. Practice with all the settings in all the effects menu to see what they do, including the shutter speed.