What figures are they?
I would recommend giving them a wash with a shade or ink or something like that, something dark. I have a big pot of this dark gray stain I got from a home improvement project - but it is basically just a dark brown shade / ink.
Then, give them a drybrush of white.
That will give you some instant shades / highlights and you can use thin, translucent colors on top to put the basecoats on.
I have no idea if that will work for your figures per se, but such techniques have been successful before.