the middle vent section isn't too bad, but the sides look a little odd
firstly - you need to learn how to use the pen tool - there are a few tutorials kicking about i'm sure, but this will avoid those horrible very square edges to the left of the car, and also help avoid the jagged edge along the bottom of the vent
you may also want to consider some styling, as it looks very bland, its just a big mass of paint, with no vents
but the main key is the details - little shadows and reflections - if you look at the base they are all over the front end, its not just one colour, and this is what makes your chop look kinda tooney.. but hey, its a first try - you can only improve
so keep on practising