Painting small icons really is this simple to do.
The whole trick is to break down the image into manageable and paintable shapes. You do NOT try to paint the whole design in one pass, most are just too complex to pull it off.
But if you break any design down into smaller shapes (that can be easily painted) and then you combine them, you'll have exactly what you're looking for in the end.
And once you have your icon down, it's time to add some battle damage.