There are things that you know how to do, and there are things that you don't know how to do. It's much much easier to do the things that you know how to do. However, you don't get better unless you try to do things that you don't know how to do. The unfortunate thing about doing things that you don't know how to do is that since you don't know how to do them, you're going to suck.
So basically, you need to accept the fact that you're going to suck. As a matter of fact, you need to suck. It's an obligation. So, what you have to do is sit down at your computer or drawing board and get that sucking out of the way. Just tell yourself, "It might suck, but that's okay, because it's a law of the universe that before things are awesome, they suck."
Anyway, here is a failed experiment with color (and coloring is something I have struggled with)(if you've seen something I've colored and thought, "That's awesome," just look a this disaster from 2009 to see the suckitude that had to come before).
This dancing C-3PO from my tumblr is an example of coloring that I know how to do (the color is a little better on the tumblr).
However, there is a problem. The problem is that metal looks like this:
It's got all these different colors. It shines. It's kind of reflective. I look at it and it's clearly gold, but there's dark browns in there, some almost white spots, it even looks like a bit of green (so brown, white, and green, but clearly gold)(what?).
I don't know how to do that.
So as practice (and in the hopes of getting a little bit of sucking out of the way), I attempted to get my metal a little bit more metallic. Basically, it's a couple layers of the brush tool in photoshop.
And then those two layers combined with that flat color layer from the top at varying opacity.
So with the finished 3PO on the tumblr, I went with the coloring I know how to do.