1) Try downloading GIMP a free image editing program.. or PAINT.NET or pay 400$ for PS4 (Photoshop), 'cause MS paint is not a good program for making skins...
2) Use a PRO kit, as this would give a huge boost at your skins' appearance x].
3) Take your time when making a skin, 'cause like someone (i can't remember now) on the forum sayed:
5) When using decals of brands use this stretching guide by JazzOn x], as then the decals will meet their proportions on the car, even if it doesn't look like that on the skin x].
6) when you have finnished the skin add a shadow layer, it will make your skin look better x].
7) to make a good preview, render the skin, and if you can't you can ask here x]. There someone always will reder it , ofcourse if you make the skin look good x].
All in all , I'm hoping you enjoy making skins, and i'm waiting for more better ones from you x]
You could also add that you can find some higher res logos here: http://www.brandsoftheworld.com/ HOLD ON A SEC! IS THAT AUTOCROSS SKIDPAD IN THE BACKGROUND?