I've wasted many an hour coming up with the below approach. It works for me, but I'm sure every one has their own preferences. My best tip is to keep it simple avoid the Barbie Doll skin by lowering the opacity of your layers. Include some imperfections; few of us are perfect after all.
I've listed the quick and dirty work flow so you can create an action straight away and then start playing with your own style.
Use or abuse
Disclaimer: I've just done this for fun ~ feel free to clarify the steps for any one. As for me, I'm off to take some photos.