If any part of your hair or layers fall at the widest parts of your face (usually your jaw or cheekbones), that will increase the appearance of width. Toth suggests getting a chin-length bob or lob.
"When the length of the haircut falls at least two inches below the chin, the style will automatically make the face shape look slimmer," he said. "The eye is drawn to the vertical lines of the hair and the hair is literally covering up the width of the face on each side."