Do NOT use the default Occlusion presets. The shadows are way too dark, and it looks horrible. You want to be able to control how dark the shadows are.
Use the MIB-Occlusion node in Maya 8.5 and change the black color to dark gray, and play with the sliders. I used 2 MIB-Occlusion nodes for the scene.
Now render the color and occlusion separately and bring them into Photoshop. Duplicate the color file and put the occlusion pass in the center. Use Multiply or Overlay for the Occlusion. Play around with the opacity. For the Color on top, use a little Gaussian Blur and screen the top color file.
A little warning about using the skin shader and rendering with Mental Ray: If your scene has 90% skin shaders like mine, it gets pretty expensive to render even with a core 2 duo processor. This present scene takes a bit over an hour to render a frame with the school’s computer and their computers are way better than mine. Good luck!