Pictures? Eek! Might be able to post some tomorrow. If you all promise not to laugh.
'Til then, here's what I did:
I used a few light coats of light grey primer. I sanded it lightly and then sprayed on a light coat of metallic spray paint.
I traced and cut out various weathering shapes in masking tape; I did the back last, and since this is my "training helmet" and I'd spent four hours cutting masking tape, it's not as detailed as the front and sides.
I then painted gold spray paint which I toned down with a mist of the grey primer.
There is gold on the back...isn't there? Or, if not gold, a kind of light mustardy yellow? I haven't seen the backs of enough people's helmets to say for sure, but it seems like a lot of people don't used any gold, but it looks like there is to me:

Anyway, when that dried I masked off some gold areas.
I then painted my greenish blue color on. What I most notably did wrong came down to what I have always done wrong any time I have painted: Impatience.
I started off with light coats, but after three I got bored and went too heavy. So it's too thick in some areas and on certain angles under the light you can clearly see streaks.
After my last coat I misted on some flat black spray paint.
When I removed the tape, I discovered that a lot of the greenish blue color bled under the tape.
I then tried to topically apply the greyish color, but it looks exactly like what it is: Someone painted blobs of grey on it; looks about as convincing as a CGI Hulk.
I'm considering buying this:
http://www.internethobbies.com/internethobbies/tesmodcarspr.html
It's cheap and might help with the streaking problem as well as bleeding under the tape; does anyone know if it works?
So, yeah. I totally suck at this. But I'm so determined to do a Fett that I refuse to be discouraged, not when I've got a support system like TDH. 
Cheers!
TJ