What is the real cause of high performance?

Deliberate practice is practice that focuses on tasks beyond your current level of competence and comfort. It requires “considerable, specific and sustained effort to do something you can’t do well- or even at all” (Ericsson, Prietula, & Cokely, The making of an expert, 2007). It is highly concentrated, mindful practice. There is a saying that says “practice makes perfect”. However, I strongly disagree.