OMG! CBG have you ever painted before????
I pretty much did what Python said and practiced and practiced. I'm still far from a professional, but after practice and practice I've managed to paint at a level I'm happy with.
Here's the P1 Diorama I've recently done to show what I've been doing...
I repainted the mask entirely and added movie accurate damage, added real metal lenses, repainted the whole gauntlet and added the fine detail of electronics and added a glowing affect to the plasma cannon to show the after heat of firing a plasma cannon. I also updated the left hand glove to have the silver armour as in the sideshow original paint the glove was totally black . . .