The Role of Deliberate Practice in the Acquisition of Expert Performance
is an article about research showing that elite performers in many fields have put in 10,000 hours of directed practice. Directed practice isn't just putting the time in--it's having goals and paying attention to whether what one is doing is contributing towards achieving them.
I recommend Kenny Werner's _Effortless Mastery_ for explaining how to lower anxiety and aim at excellence (one's own personal excellence, not a generalized standard) rather than at avoiding mistakes. It's specifically about musical performance--he's a jazz musician who beat paralyzing anxiety and procrastination--but has general applications.