Here's the colouring tutorial requested by
lil_brokenangel. Unfortunately, it was sized down after I uploaded it, so it's a bit hard to see the differences, but it's still readable.
Hope it's found useful -- and remember, experimenting is the best way to make icons! I'd love to see what you come up with. :)
So without furthur ado, how to go from this:
to:
Examples of other icons made with this (or similar) colouring: