Michael Mauboussin (from Think Twice) on Deliberate Practice:
Let me emphasize one point. I suggested that people become experts by using deliberate practice to train their experiential systems. Deliberate practice has a very specific meaning: it includes activities designed to improve performance, has repeatable tasks, incorporates high-quality feedback, and is not much fun. Most people – even alleged experts – do not come close to satisfying the conditions of deliberate practice and, accordingly, do not develop the necessary abilities for reliable intuition.