Deliberate practice, according to noted cognitive scientist Dr. K. Anderson Ericsson, requires four conditions:

  * well-defined task
  * appropriate difficulty
  * informative feedback
  * opportunities for repetition and correction of errors.

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  * http://www.khanacademy.org/
  * http://www.ciw.edu/multimedia_content
  * http://nptel.iitm.ac.in/
  * http://webcast.berkeley.edu/courses.php
  * http://oli.web.cmu.edu/openlearning/