Her Atmosphere. How she holds herself, how she sits, how she walks, how she dresses. how much her smile is part of her rather than tacked onto her face. When she talks, or chooses to be quiet. How much her image seems to fit, rather than is something she's trying to put on. Gotta be comfortable with herself, or else you're just going to be dating narcissistic/insecure/headcases.
Get that 'air' about you, and anyone can be considered better looking than a still photo shown to a stranger might suggest.