I'm just learning too. But I would say your rooster has a nice level back. The tail is a little upright at the moment, but that may change as he matures. For 12 weeks he appears to have good substance.
Good, level wing carriage.
He is not nearly as colorful as my 3 boys were, so I wouldn't worry too much about his color yet ( though they do get a little more as they finish out).