It's actually more convenient when you number you pictures. SO(I number things to adjust, not photos):
#1 Reflections [#8-#11]
#2 Backgrounds (people never enhance the look, well only models) [1,2,3,8,9]
#3 Get a polarizer. [all photos]
#4 Shadows. Shoot only the bright side of the car when you don't have any additional and/or adjustable lightning
Overall: F-.
Just kidding. I'd give it an overall score of 6.5/10. Keep shooting. Get an external flash (if you got pennies in your pocket ). Post here and learn on critic. Well if you treat photography as I think you do.
not bad to start. i would just suggest not cropping them SO close. the first few the edges are almost cut off the car. as suggested on a sunny day like that a CP would help.