1) Three-point lighting is the standard lighting setup for interviews, using a key light, fill light, and backlight to properly illuminate the subject and separate them from the background.
2) The key light should be the brightest light and illuminate one side of the subject's face to make them stand out from the background. A fill light is used to reduce shadows and high contrast.
3) A backlight separates the subject's shoulders and neck from the background by shining on the back of the subject. Proper three-point lighting is important to properly light interviews.