The phrase "to master the craft" means becoming highly skilled and knowledgeable in a particular skill or trade. It entails reaching a level of expertise where one has complete control and understanding of their chosen field. Full definition
Much is to be said for mastering the craft of novel writing and learning the industry before seeking any kind of publishing route. (darcypattison.com)
The Catholic writer must have the passion, talent, and ingenuity to master the craft in strictly secular terms while never forgetting the spiritual possibilities and responsibilities of art. (firstthings.com)
In a country obsessed with perfection, very few artisans can claim to have truly mastered their craft. (departures.com)