A great procedure outlined by Mitch, one of the best GRD III photographer I am aware of. You can read full review and procedure here
1. Pull back on Boost to 75%.
2. Apply moderate Sharpen and Edge Sharpen.
3. If necessary adjust the Exposure.
4. Use Highlight Hot & Cold Areas to identify where highlights are blown out (shown in red) and shadows go to black (shown in blue).
5. Use the Recovery slider until the red showing blown out highlight disappears.
6. Use the Black Point slider until the blue showing shadows that go to blackj disappears.
7. Occasionally, if the focus is a bit soft, apply the Definition slider, but most of the time I just use the Structure slider in Silver Efex, which increases mid-tone contrast.
8. Start Silver Efex, which converts the image to B&W. In Silver Efex I adjust the overall contrast and brightness and also do selective burning and dodging. Often, I use of the presets that reduces exposure and then do strong a Structure move that brightens the image and then select on of the film presets, often Tri-X, which increase contrast by compressing the shadows and highlights somewhat and adds grain.
Silver Efex has various film presets but these should not really be thought of that particular film, Tmax 400, for example, but shield be looked at as different tonal and contrast, as well as color sensitivity components. That means that I select the film presets that looks best for a particular picture, and don’t use batch approach.
I then do burning in and dodging of parts of the picture using the Silver Efex Control Points. I like these Control Points a lot better than using Photoshop selections because the way of doing is more like dodging and burning in the darkroom. One thing one finds when starting to use Control Points is that a particular CP may affect some tones or areas that one didn’t want to change. While the size of the CP circles can be reduced, sometimes they still affect other areas. The way to avoid this is to put down a new CP in that area, without adjusting any of the sliders: this will keep the tone or area under the new CP from changing, from being affected by the other CP on which one has moved the Brightness or Contrast sliders.
9. Finally, for some pictures I apply some vignetting or some burning in of some on or more of the sides of the rectangle of the image.
10. Once I finish with Silver Efex and the processed image shows up in Aperture I usually increase contrast a bit by pulling in Levels the black and white points.