Thanks to Miss Maudie, Scout learns that it's okay for ladies to potter around the garden wearing a straw hat and men's coveralls. Miss Maudie also teaches Scout that it's a sin to kill a mockingbird. What she means by this is that there are creatures who are put on this earth to do nothing but good.
Miss Maudie teaches the children several life lessons: To show sympathy and consideration for others, to exercise moderation, to be humble and satisfied with what one has, and to not tolerate hypocrisy.