Thanks, glad you like it
For the coils I simply followed
this video (hobby cheating is one of my favourite tutorial series)
The dust on the coat is simply vallejo rust pigment, super quick to do.
As for the metallics I always struggle with highlighting metallics and am to lazy to try out
NMM 
This time around I simply started by spraying the entire miniature with metal color gunmetal and then zenithal highlighted it with metal color silver. I think it turned out ok on smaller elements, but I agree it's a bit flat on bigger surfaces.