Ask the local
GW staff/regulars about what paints would look best, preferably starting with a warm yellowy brown up to some brighter yellows (I am terrible at remembering paint names...) I would highly recommend trawling through Google images looking for objects made out of gold as your reference art for highlights/shading.
The technique should be a fairly straight forward process of layering, just like you would use for the rest of your model. You may want to experiment with blending, for which I would recommend getting some paint extender. My first
nmm attempt was terrible as the paint kept drying before I could do any blending between shades :(
I'm still fairly new to
nmm too so if you figure out any handy tricks, please share them