> ... the most important thing you can do is do a lot of work ... It is only by going through a volume of work that you will close that gap, and your work will be as good as your ambitions

This volume of work coupled with a closed feedback loop (Do - observe - measure - tweak - Do) allows for achieving astonishing results. Also taking a skill apart, practicing and improving individual skills and then putting it all together is the basis of acquiring and mastering skill.

I do not believe a mentor can help with acquiring skill. But a good mentor can quickly identify and guide you to the parts that need attention and practice.