You're off to a very nice start. Looks like you've got a good handle on the brush control (getting the colors in the right place and not having the metallics go into the reds and vice versa).
If you're looking to improve, I'd say the next step would be to work on the lighting and shadows. Take a look around the web at Zenithal Lighting tutorials. There's a good one at MassiveVoodoo (
http://massivevoodoo.blogspot.com/2010/08/tutorial-zenithal-lightning-work-order.html), but you can find plenty out there.
That red can be a tough color to work with. If you highlight with white, it turns pink. If you highlight with yellow, it turns orange. Sometimes mixing in a light skin tone can give decent results. But, whatever you use, a final layer of red glaze (either GW's bloodletter or a red ink) can help turn those highlights back from pink or orange into more of a red.
When it comes to shading, a dark red can work fine. But you can get interesting results by using other colors. You could create your shadows by mixing into the red, a dark brown, a dark blue, or a dark purple (a little bit at a time to help create the blends). Each will produce slightly different effects. Experiment and see what you like!
Just a couple tips that might help with your next project. The most important tip I can give is to just keep painting and have fun with it! The rest will come with time.