Miss Caroline is a bit of an outsider in Maycomb. She is from Alabama but she's from Winston County which, according to Scout, is notably different that Maycomb.
Miss Fisher is a new, idealistic teacher. Apparently, she is a proponent of John Dewey's theories on education which stress the importance of experience and education as social interaction. (We get this information from Jem who mistakes John Dewey's educational theories for the Dewey Decimal system.) However, Miss Fisher, being a new teacher, is too single-minded. She chastises Scout for having learned to read on her own, even though this would have fit one of Dewey's criteria that education teaches one how to live and interact with others. Miss Fisher is also oblivious when she tries to give Walter Cunningham Jr. a quarter for lunch, saying he can pay her back tomorrow. It doesn't dawn on her that Walter might not be able to pay her back. Scout takes it upon herself to educate Miss Fisher about the Cunninghams:
The Cunninghams never took anything they can’t pay back—no church baskets and no scrip stamps. They never took anything off of anybody, they get along on what they have.
Scout tells Miss Fisher that she's embarrassing Walter. Miss Fisher pulls her aside and smacks her with the ruler. As they leave for lunch, Scout notices Miss Fisher apparently crying. The class will also have to "educate" Miss Fisher that the Ewell children come to school on the first day and never come back. Miss Fisher's surprise and concern shows that she does care about her job and the children.
Miss Fisher seems like an idealistic, first-time teacher who had come to her first job with high hopes, only to find that she (the teacher) still had much to learn via the actual experience of teaching in a new place.