Here's a tutorial showing (at 2x speed) exactly how I painted the non-metallic metal on the Phoenix Guard I just did. There were a bunch of requests on youtube for a tutorial like this where I film the whole process. I've mentioned before that I use Reaper paints for this, but in this I have used GW paints. I get a lot more requests for the specific GW paints, but I actually prefer the Reaper ones for NMM. They have a slightly more yellow look straight out of the bottle, which I like. To due true NMM you would want to use more steps, but this is a quick process that is great for blocks of troops.