you can use layers and liquify with the brush tool to get rid of the distortions that liquify causes.
in the "layers" window, you can select the layer you are working with and isolate the layer so that the brush you are working with will not paint anywhere beyond the edges of the object within the layer. for instance, if you are working with a layer that is a boob and you make all other layers invisible so that it just looks like a boob on a white and grey checkerboard, your brush will not produce marks anywhere except within the boob shape itself. to do this, where it says "Lock:" on the layers window, click the first button next to it (the button looks like a little checkerboard and is called "lock transparent pixels.") By doing this, you will have an easier time shading or highlighting the edges with a brush or burn/dodge tool.
It is also helpful to download new brushes for painting textures like skin. If you search the web for "skin texture photoshop brushes," or "hair photoshop brushes," et cetera, you will find many, especially through deviantart. these download as .abr files, which you place in the photoshop brushes folder. they may then be found and selected for use in the dropdown menu of your brushes prompt. if you use these with the right amount of subtlety, the textural effects can be quite good.
to get the right colors to use, use the color dropper tool from the body or garment you are trying to replicate. but bear in mind it takes practice and time and subtletly to get skin painting right. in old master or academic paintings, forms were painted through numerous thin transparent glazes atop one another. in photoshop, it tends to be the same. one cannot simply paint skin by choosing a skin-like color anymore than a painter could paint skin just by buying a tube of skin-colored paint and putting down a coat of it. start with a solid base color, add the darker tones where shade is necessary with the brush set at 0% hardness, and then gradually make the brush a lower and lower % of opacity to build up the appearance of flesh