It's pretty basic. To get it a bit more interesing you'd probably want to follow the car's curves more instead of ignoring them. If you're using Photoshop check out the skinning templates Bunta has made. Keep at it!
My wife thankfully is not affected by breast cancer, but is very involved with charities and fundraisers. I made a skin for that purpose, feel free to use, but not abuse, please. BTW, the windshield banner words were her idea.