Well, I don�t make dolls but for any Photoshop art work users this is fun.
You can take a picture of a doll and get a real picture of skin, and by making a selection and messing with the blending modes and lightness values in Photoshop you can make the doll look like it has real skin. I used a good camera on the doll.
Here is the tutorial.
http://nickabc.tripod.com/skin_tut.htm

By the way, I Need to update that site, these pictures are kind of old.