I've recently came across this wonderful site: http://www.drawmixpaint.com/ and I was surprised by the way realistic painter Mark Carder explains so easily and practically the steps to learn painting and creating your own supplies for the purpose. I've even made a proportional divider for myself that works perfectly, he also does great hangouts about art related topics on Google Plus if you are interested.
Check out the complete course on how to paint realism with oil, I'm sure it will not disappoint you:
