Tell your child, spouse or employee that they have no gift for a certain thing, and are doing it all wrong, and you destroy almost every incentive for them to try and improve.

But use the opposite technique, be liberal with your encouragement, make the thing seem easy to do, let the other person know that you have faith in his ability to do it, that he has an undeveloped flair for it, and he will practice until the dawn comes in the window in order to excel.