According to the Centers for Disease Control and Prevention, the best way to thoroughly wash hands is to wet hands with warm or cold running water, turning off the tap, and applying soap. Next, lather the hands by rubbing them together with the soap.
While lathering, make sure and lather the backs of the hands, between the fingers and under the nails. Lather for at least 20 seconds. Next, rinse the hands well under clean, running water. Finally, dry the hands with an air dryer or a clean towel. If no water or soap is available, use an alcohol-based hand sanitizer containing at least 60% alcohol.