Gary Marcus’s Guitar Zero runs with this notion of doing practice right:
“Hundreds of thousands of people took music lessons when they were young and remember little or nothing,” he points out, giving lie to the notion that learning an instrument is easiest when you’re a kid. The important thing is not just practice but deliberate practice, “a constant sense of self-evaluation, of focusing on one’s weaknesses, rather than simply fooling around and playing to one’s strengths. Studies show that practice aimed at remedying weaknesses is a better predictor of expertise than raw number of hours; playing for fun and repeating what you already know is not necessarily the same as efficiently reaching a new level. Most of the practice that most people do, most of the time, be it in the pursuit of learning the guitar or improving their golf game, yields almost no effect.”
[...]
In an article titled “It’s Not How Much; It’s How,” published in the Journal of Research in Music Education in 2009, University of Texas-Austin professor Robert Duke and his colleagues videotaped advanced piano students as they practiced a difficult passage from a Shostakovich concerto, then ranked the participants by the quality of their ultimate performance. The researchers found no relationship between excellence of performance and how many times the students had practiced the piece or how long they spent practicing. Rather, “the most notable differences between the practice sessions of the top-ranked pianists and the remaining participants,” Duke and his coauthors wrote, “are related to their handling of errors.”
The best pianists, they determined, addressed their mistakes immediately. They identified the precise location and source of each error, then rehearsed that part again and again until it was corrected. Only then would the best students proceed to the rest of the piece. “It was not the case that the top-ranked pianists made fewer errors at the beginning of their practice sessions than did the other pianists,” Duke notes. “But, when errors occurred, the top-ranked pianists seemed much better able to correct them in ways that precluded their recurrence.”
Because playing guitar is all about getting the maximum score on the expertise scale. And here was I thinking it was about having fun, being cool, and picking up chicks.