Texturing & Shading
I used Photoshop to make the textures and I used a combination of real photos (Fig.10).

Fig. 10
For the skin I used the Mental Ray SSS shader. I then made a diffuse map, epidermal map, bump map and specular maps for her skin (Fig.11).

Fig. 11
I used Mental Ray to render the scene. The settings of each material can be seen in Fig.12.

Fig.12 - click image to enlarge
The sweater was done with the Mental Ray architectural material (Fig.13) and the sweater detail can be seen in Fig.14

Fig.13 - click image to enlarge

Fig. 14
Hair
Hair is an important part of any realistic character. I used Hair&Fur to create the hair for the girl and the settings can be seen in Fig.15 - 16.
Fig. 15
Fig. 16
Lighting & Setting
I used five Free Area Lights with Final Gathering applied. All of my light and render settings can be seen in Fig.17.

Fig. 17
Compositing
The render times were becoming crazy, so I found it much easier to render the hair in a separate part, and then to combine the parts again in Photoshop (Fig.18).

Fig. 18
And with that, my image was complete (Fig.19)!
Fig.19 - Final Image