http://graphicssoft.about.com/gi/dyn...FHSasmoo0.html

I suggest first getting the tools of the trade. Photoshop works nicely

Then using the plugin I linked above will let you remove skin blemishes.

Then check out the following for an indepth on fixing all the other stuff:

http://graphicssoft.about.com/od/dig...ialtouchup.htm

This is more like art... so you'll have to use your artistic talents to make it look natural and balanced. Happy practicing. If I find any more articles I'll try to post them.