Soldato
I tend to find with gold/metals it's often best to do two or three thin coats.
It might also be worth trying an intermediate colour between the black and the gold to avoid having to do the gold straight onto the black (it often helps with other colours).
This is usually what I do. I go for a dark-medium brown over the black, then drybrush the gold over the top. It helps to create some nice shading, too.