Begin with praise and honest appreciation. Call attention to people's mistakes indirectly. Talk about your own mistakes before criticizing the other person. Ask questions instead of giving direct orders. Make the fault easy to correct. Make the other person happy about doing what you suggest.
Dale CarnegieWhen we hate our enemies, we are giving them power over us: power over our sleep, our appetites, our blood pressure, our health, and our happiness.
Dale Carnegie