I wanted the black to become the backdrop for the other elements on the model, particularly the gold. After priming black (of course) I began by drybrushing the armor areas with metallic black. This keeps the black from becoming too tinted with blue or grey, while also adding a degree of luster to the plates and allowing the edges to catch the light.
I tried a new technique on the gold, and I'm pretty pleased with the results so far. I basecoated with old Calthan Brown, then did a messy highlight with new Averland Yellow. I then went back over it with a layer of new Auric Armour Gold. The gold covers well by itself, but I found that the colors underneath show through and add a good bit of depth to it.
I'm still not 100% sold on the black and will probably keep experimenting, but I'm happy with the gold for now. Thanks for reading, and let me know what you think!