When someone makes a mistake, it is our natural instinct to correct them. However, instead of telling them that they are wrong, show them how they are wrong. This will enable them to actually learn from their mistakes.
Show others how they are wrong instead of telling them how they are wrong.
A simple example of this concept in action is a manager of a store noticing an unattended customer waiting at the cash register while the cashier is off in the corner on his phone.
Instead of reprimanding the cashier, the manager stepped up to the counter and waited on the customer himself. Noticing this, the cashier immediately felt embarrassed, and the next time a customer was at the counter, the cashier was there too, ready to wait on them.