How to shade professionally ?

Hey everyone,

I am looking for some tutorials that would teach me how to make realistic materials in blender, maybe teach me more about the shaders in the node editor. I want to make materials look realistic. Would be nice if you guys can tell where I can find tutorials of making a brushed metal material but I would also like a general course in shading.  Are there any tutorials in blender that teach that ? ( other than the Fundamentals of shading course and the Fundamentals of texturing course )