In terms of appearance, these 2 quotes above fits most. It seems guys with dimples are cute when they smile adorably. In terms of personality, The bottom 2 quotes described best. Guys looks much cuter when they act shy, blushes a lot or act cheeky.
Traps. Anime, manga, novel and real life "traps". Like it or not, them traps be triggering you with mixed feelings, I tell ya! The horror! Every other "cute" guy a girl sees is based on their preferences. And there are also the minorities... the ones that find "disturbing" things about particular guys "cute".
I have noticed that if a guy is shorter than you girls and is shy, he will automatically become cute in the eyes of the taller girl.
dunno The last person I remember being cute was a 6 and 1/2 feet tall (~195 cm) youngish cashier. His face was a little bit soft, but not overly so. I've seen much softer faces without thinking they were cute. So I dunno what made me think "cute", but it was strong enough that it really made me speechless for a little bit. (...poor guy probably thought I was staring because of his height...) Something about the way a person carries themself maybe?