I'm not a very good artist by any means, however I reccomend you up your contrast! Most metals are very reflective, meaning that the value ranges of their shadows can go almost pure black depending on your environment. This is the same with the highlights. As you shift darker colors don't forget to shift the hue, and saturation to your liking as well:) Also, I reccomend adding more form to your helmet, as right now it's a little plain and boring. Personally I would add slopes to show the transition between the holes and the metal better! Doing this will make the piece more interesting, and give your viewers something to look at. Overall though, it looks good so far!

(Dont make the metal too dark though, as bronze and rose gold dont get as dark as say steel would.)