The shade was done the old way with the airbrush, but the highlights were drawn with a solid brush. Note that the cylindrical collar reflects in a sharp band, and the more rounded metal part reflects in more circular spots.
Here's another example and separation of another simple detail area, the eyes:
Again, the bright spots were drawn with a solid brush, but this time the shade on the irises was drawn with a very, very small airbrush, in lines radiating from the pupil.
Well, I think I've shown that these small and simple detailed surfaces can be made just by picking the right brushes and putting a little extra effort into shading. But what about larger areas? You wouldn't want to draw every single strand of fur independently. Next, we'll start playing with custom brushes and the smudge tool to create some basic textured long fur.