I then create another smaller oval selection to clear the bottom of the highlight. You should have a crisp airbrushed shade. (Fig10)
Simply motion blur for effect. Besides giving character and movement, motion blur blends the edges with finesse. (Fig11)
Now add your final brighter highlight using the same technique. (Fig12)
Finally, soften the edge of the ball. (Fig13)
SMUDGE, DODGE AND BURN TOOLS
I do not use these tools for painting, in particular when creating consistent tones for cartoon or stylized textures or in general when painting gritty textures.
It is of my opinion that certain tools do more harm than good. Just because a tool exists is no reason to use it. I have seen painters use the smudge, dodge and burn tool to the detriment of the texture.
There are of course occasions to use them, but I really believe that skin textures (or many other surfaces) is not one of them. Take another look at a number of skin tones in games and see how some characters look like they have face powder on.
These tools have a bleaching effect on skin. They tend to lack pigment/hue quality leaving a dirty or washed up look. Try instead to use colour to simulate a bleached look. Another way sure to surprise you, are Photoshop's layer blenders in the layers window. Blenders like Overlay and Screen can be a revelation.
What I do is paint the tone variations normally then attempt to see what it would look like in some of the layer blenders. You may need to modify the original hue slightly in image>adjust>hue/saturation menu or adjust the opacity of the blender later.
If you know how to paint well, try to use hue rather than the aforementioned tools above to simulate what you need. Your textures will end up looking richer.
Back to our metal ball, I selected the background with the selection tool, filled it with white on a separate top layer then Gaussian blurred it to soften the edge of the metal ball.