You may think that your rehearsal of a job interview was flawless, but your opinion isn't what counts. Or you may believe you played that bar of the Brahms violin concerto perfectly, but can you really trust your own judgment? In many important situations, a teacher, coach, or mentor is vital for providing crucial feedback.
Deliberate practice is above all an effort of focus and concentration. That is what makes it "deliberate," as distinct from the mindless playing of scales or hitting of tennis balls that most people engage in. Continually seeking exactly those elements of performance that are unsatisfactory and then trying one's hardest to make them better places enormous strains on anyone's mental abilities.
The work is so great that it seems no one can sustain it for very long.
Doing things we know how to do well is enjoyable, and that's exactly the opposite of what deliberate practice demands. Instead of doing what we're good at, we insistently seek out what we're not good at.
Then we identify the painful, difficult activities that will make us better and do those things over and over. After each repetition, we force ourselves to see - or get others to tell us - exactly what still isn't right so we can repeat the most painful and difficult parts of what we've just done. We continue that process until we're mentally exhausted.
If it seems a bit depressing that the most important thing you can do to improve performance is no fun, take consolation in this fact: It must be so. If the activities that lead to greatness were easy and fun, then everyone would do them and no one could distinguish the best from the rest.
The reality that deliberate practice is hard can even be seen as good news. It means that most people won't do it. So your willingness to do it will distinguish you all the more.
Geoff Colvin, Why Talent is Overrated