Thanks for all this! Seems consensus is I need to work on my layering, and I couldn't agree more. In fact, I was actually trying to achieve a more toning effect on the cape, from Kador Blue at the center fold behind his/her behind, and towards Alaitoc Blue at the edge. The transition was made in several layers, step by step blending in the lighter blue. However, the edges between the different layers became too sharp, so I tried to smooth the transition with Drakenhof Nightshade mixed with Lahmian medium (1:3) in several layers. And this in the end pretty much screwed the transition up ... I think I'll try wetblending next time.
Metals: I experimented with shading with Druchii Violet (I think it show) but perhaps I could've gone with a deeper shade?
As I wrote, I've really just started painting (this is the first model I've tried to do with a more "clean" look, I've mainly played around with a grittier style before) so I'm very much into experimenting and learning. All suggestions are welcome!