I'd support Golgotha's suggestion in that in my experience, it works best to pick a general viewing angle for the figure, i.e. front or back, and place the "lightest reflections" accordingly. Here's an orb I did a couple of months back, which I am quite happy with:

As you can see, I painted the orb in subsequently lighter shades from top to bottom. The bottommost layer, which touches the goblin's skin, is almost pure orange, but all the shades have some of the red inside. Imagine painting rings running around the orb in a horizontal fashion.
The top pin light is painted in pure white placed within the most likely viewing angle, and the whole affair got three slightly thinned coats of artists' acrylic varnish to top it off. The whole orb took me about an hour in total, with most of the time spent painting other areas while the individual layers dried.