Your frames should align horizontally with your eyes. The width (eye size) of your frames should not be more narrow than the width of your face at the temples.
Cheeks
The bottom edge of the frame should sit away from your cheeks to avoid contact.
Nose Bridge
Your glasses should fit comfortably on your nose without digging in or slipping down.
Ears
The arms (temples) of your glasses should fit comfortably and securely over your ears.