You may have seen this already, it’s on delicious, but it’s something I’ll read over later so I want to mention it. This airbrush tutorial is very detailed, showing each step with accompanying screenshots.
The result is quite a stunning image in the Playboy tradition of perfect skin and tones. Fake but it’s what people want!
I posted a similar touch-up tutorial a few months ago, but it concentrated on general techniques for giving a portrait more punch.