Doesn’t take much
I have acquired professional-level skills in career counseling, journalism, rose breeding, screenplay writing, and strong amateur-level skills as an actor and play director without ever having taken a course in any of the above.
And how he did it is unbelievably simple for anyone with some time and a lot of self-confidence. For the record, this guy is a top-of-the-field career counsellor and world-class rose breeder.