What are some of the ways that actors identify how to move and speak for a particular role?

Explanation:

In every play or movie, actors must read the script but paying attention to details that give them the keys to personify perfectly. So, in most cases actors analysis the character, behaviour, social class, profession, the psychology of it, the state of its emotions.

"why don't you like me the way i am? " i cried. "i'm not a genius! i can't play the piano, and even if i could, i wouldn't go on tv if you paid me a million dollars! "

explanation:

the conflict between jing-mei and her mother is over jing-mei's piano lessons since her mother wants her to become a prodigy but she does not want to play it any more.