Pay attention with the following. the scale of the eye, nose, mouth, chin.
Notes:
Baby 1 to 5 year old. big eyes, tiny nose, tiny mouth, big rounded chin
Kid 6 to 12 years old. follow the scale.
Teenager 13 to 19 years old. follow the scale.
Adult 20 to 40 years old. follow the scale.
Middle age 40 to 50 just add wrinkle. follow the scale.
Grandpa 60 to 80 more wrinkle, white semi bald hair. follow the scale.
Good luck.