Hey guys, I like to believe that I am fairly competent when it comes to using programs like photoshop to do basic picture blending and using layers, etc. But when I see all of the fantastic works of art that people make when they render future versions of cars and stuff I feel like a man who brought a Porsche Boxster to a race for Bugatti Veyrons.

I was wondering if there are any tutorials online that you can direct me to or if there are any quick tips that could help?

My goal here is to be able to make a decent rendering of a coupe into a convertible or vice versa, this is sort of my threshold. Learning how to do anything more is great, but honestly, since this is just a hobby, I'll take any help I can get.

Thanks guys!