When you are photographing someone, part of the face may be in shadow, particularly if they are sitting by a window. Here are some tips for reflecting light onto the dark side of the sitter's face.
Use a square of white card, a mirror, or kitchen foil glued to cardboard to 'bounce' the light onto areas in shadow. A projector screen makes an excellent reflector of light. Remember to keep any reflector off-camera so that it won't appear in the picture.
