The three point lighting technique has long been a mainstay of photography, videography and film. It involves the use of three strategically situated lights to create the best possible image of a subject, often a person. See diagram below to show where the three lights should be placed.
My television production/editing students study three point lighting. I like to give them a hands-on (and lights on!) project so they can set up the lights and take photographs to show the changes made by the use of the key, fill and back lights.