I painted white metal miniatures back when I was into War gamming/Dungeons and Dragons (late 70's early 80's).
The same painting skills and techniques are used. Shading, weathering, dry brushing, etc.
I acquired hundreds of the white metal figures(still in original packaging) and a few plastic figures (horrible detail) when a local toy/game store (Toys By Roy) closed its doors.
I remember the miniature makers had their equivalents of plastic model makers. Horrible detail (like Aurora), lots of "flash" (like Lindburg) and the better ones (Revell/Monogram). The only maker I can remember is Ral Partha, one of the better ones.
The newer miniatures I've seen are absolutely beautiful, fantastic detail. They seem to be made of a plastic or ceramic material and from what I hear takes paint very well.
The "Hero Clic" line comes prepainted and are pretty well done.
I'm not sure the ole eyeballs would be up the the task of painting these little guys.