Here’s a video where John Mayer improvised a song on a livestream—and it’s marvelous watching this. If you haven’t seen this yet, it’s definitely worth a few minutes out of your time to see how he’s conjuring this out of thin air:
Also, even at his level he says it still “requires a stupid bravery”. To most people watching this, it’s mesmerizing to see what he comes up with on the spot, but it still takes something out of him, there’s still an element of overcoming.
Wherever you are in your creative journey, there’s a lesson: You must overcome. Overcome whatever is in the way of you practicing your craft and do your prolific practice.