Finding a mentor probably helps most and is the hardest. I know a few good people who wouldn't have got where they are without a mentor. I never found one and I'm 10 years in the game now. So I'm probably cursed to mediocrity, haha.
Call me a pessimist but I doubt the vast majority of people will ever find true mentorship. Would it be nice to have a more experienced and talented developer take a personal interest in your career and technical development? yes, of course it would, but it's unlikely at best. I'm sure self study, discipline and "grit" matter far more.
Personally, I was fortunate enough to have a mentor when I was starting out and it rocketed me to a strong position in my career and I couldn't be more grateful. I try to actively mentor 1 or 2 people a year as a result.
It's been mostly very successful so far.