The first opinions that we get are from Elizabeth's perceived perception; after she comes into the house after her 3-mile walk, she is sure that Miss Bingley and Mrs. Hurst "held her in contempt for it." This is just Elizabeth's perception though--is she right? Elizabeth is quite a discerning character, and in chapter eight, we learn Miss Bingley's true opinion of Elizabeth. Although nice to Elizabeth's face, when Liz leaves the room, she pronounces that she had bad manners, was too prideful, and had "no style, no taste, no beauty." Mrs. Hurst agreed immediately.
The two ladies then extrapolate their opinion of Elizabeth, and generalize it to all of the local gentry; they consider Elizabeth a representation of country folk. They decide that she represents a "country town indifference to decorum." Although vacationing in the country itself, they hold themselves above the rather ungenteel practices of the local people, and esteem themselves as being of superiour breeding, education and behavior. Because Elizabeth herself is not "accomplished" at playing the piano or painting, and instead prefers to read. Also, her strange behavior in regards to walking, unescorted, for miles, lead them to believe that she doesn't quite understand what is appropriate or not. Their observations of her family members at the dance previously confirm their suspicions of the country people being unrefined, and they assume everyone in the area is.
I hope that those thoughts help; good luck!