Here are a few pictures of the colours I use for the metal trim and what my palette looks like before I start. I use little nuisances of reds and green for painting the armour so my palette looks a bit cluttered but it seems to be what works for me. I use various techniques like stippling, glazes, and washes to achieve the looks I like. Then I toss in some battle damage here and there, mostly where the blends aren't so nice (muahah).
@Scherdy sorry for the late reply, and thanks for your words. I used vallejo colours Hull Red, Sepia Ink, bleached bone, and white for the wraith bone. In terms of the free hand I used pure white over a flat, dark green face place, to bring out the volumes (wanted to make the freehand feel like raised rivets).I worked my way down in from the white lines, with various green, greys, blues, and subtle red, as oppose to a normal blend (say for flat piece of armour) where I would work my way up to brighter colours. Hope that helps.
Here is an update, still not sure I am happy with the axe will still do some tweaking with the volumes and smoothing things out.
More to come.