I'm with sponge on this one. Why do people always get offended when they get some negative criticism I don't understand.
That mercedes skin is clearly a 2s job. There was no effort, no imagination, nothing in it. Just 3-4 terribly low res logos. It's not an excuse that you don't know how to skin, don't have the software, beginner etc etc etc. You can still try, noone's skins are perfect in the begining but at least people try to put some effort on it, try and make some shapes, put some colors, don't just copy paste one logo 5times. I know some pople like simple skins, but this can barely be called a skin.
I completely agree with Sponge, you should definitely put more effort into your work. Look around the forum here or Master Skinnerz, you will find a lot of guides, resources, tips etc which will definitely improve your work. You can also dedicate a thread for your first skin where you put considerable effort in, ask people for criticism, improvement suggestion etc, that's the only way to learn and to produce some quality work.