Try to run the dishwasher only when it is full of dishes. In most cases running your dishwasher with a full load of dishes will use less water than washing the same number of dishes by hand.
Many newer dishwashers require little or no advance rinsing of dishes. Read the instruction manual for your machine to determine if you can minimize rinse water usage.
In most cases it is more efficient to use your dishwasher to wash a full load of dishes than if would be to wash all those dishes by hand. Take advantage of the conserving benefits of your dishwasher.
The washing time involved with a dishwasher is minimal in cost. The drying time can be expensive at 1500 watts per cycle. Air dry the dishes or dry them by hand.