Justin Guitar seems like a great resource. Thanks for sharing!
It's an odd thing giving advice from the perch of mastery. Justin emphasizes the "key" is transcribing songs. Similarly, as a go/baduk acolyte, I'm told by dan players to study tesuji, but most of my practice is playing actual games, just as it is playing actual songs.
Masters fall into the trap of thinking well, what would I do to get better? Because of their own preternatural talent and a 360 view of the discipline, they don't quite see that the less talented, casual learner needs practice to be a non-chore to stay motivated.