I usually notice their most prominent feature. I don’t generalize a specific feature to all people because all people don’t necessarily have nice eyes, but some people might have a really nice smile. :)
Its meaning is this : An indivisible part of characteristic/temper.
Physical: Honest i see their nose, eyes.. all about in their face because their personality can see from face.
Personal: be friendly.. ;)
Each person will have a individual feature that make others notice them.
But normally, i will notice to their hair and eyes:D
his/her smile.. that's will guide me either to be friends with them or not
eyes and a sense of humour)