I’d like to share this old video with you that documents Gypsy guitarist (and fiddler! I hand no idea) Dorado Schmitt teaching his son, Samson, who looks to be around 10 in this video. They’re playing one of Django’s solos over his tune Minor Swing, no small feat. It’s a great example of teaching and learning for many reasons.
Few musicians I’ve talked to have ever been taught how to practice. We’ve all been pretty much on our own. When teachers do influence us, it’s by making reasonable and very specific demands that make it clear exactly what is to be practiced if not exactly how to go about it.