Smooth skin, can be acheived duplicating the background layer, then applying some gausian blur to the duplicate layer. Mask off or erase the areas you want to be sharp, so the background shows through.
The easiest way to get the cracked/flake effect would probably be to use an image of some cracked/flaked paint, desaturate it, then paste this into a new layer overlaying it over your picture. Set a blending mode to allow the cracks to combine with the background image, creating a texture. Play around with the opacity to give the desired look. Mask off the areas of clothing and background, so just the skin remains textured .
Don't forget the liquify tool for the Barbie proportions . You can also use the liquify tool to bend the cracks into and around features, to give a more realistic 3d cracked surface.
All in all, a bit of work to do well, but should be a good learning curve.
