TheFragilehttps://www.youtube.com/user/CurseCS/videos
That's adreN's youtube channel. It's constantly updated with extremely useful stuff from settings, movement, spraying, spam spots, taking sites, defending sites, useful flashbangs/smokes/molotovs, and match comms.
He makes an effort to try to help people improve instead of just MMing or pugging. I believe he main calls for his teams and takes an input lag hit from streaming matches to use as a teaching tool later. It's really too bad there is only one player as good as adren doing that sort of stuff. He's the real deal.