How can the reader see Scout change during each chapter? How do you know this?

In the beginning of the novel, Scout is a proud and spunky tomboy. She has no interest in lady like behavior. In Chapter Nine, when her uncle asks if she'd like to be a lady, she said "not particularly."

As she gets older, and her interest in Dill grows to that of a boy on whom she has her first crush, the desire to act and look a bit more like a girl surfaces. She beings to separate herself from the boys and cooperate during the ladies' luncheons. Eventually, she comes to understand and appreciate the qualities she never liked in her aunt. Notably, in the way she emulates Aunt Alexandra in Chapter 24, "After all, if Aunty could be a lady at a time like this, so could I."

Aunt Alexandra taught her how to be a lady technically...