If I were you, I would want to answer this question by thinking about the way that characters in both of these great texts deliberately use and master the societal norms of Edwardian England for their own purposes to manipulate others. Clearly, in "The Open Window," it is Vera who perfectly masters the way she is expected to act and speak in society to devastating effect, weaving compelling tales that completely ensnare the poor, susceptible Framton Nuttel. Vera is shown to be an expert of social norms, speaking only "when she judged that they had had sufficient silent communion" and entertaining the gues while her aunt prepares herself. In addition, she is quick to sound out this strange guest, identifying his lack of knowledge about the family before having her fun and telling her tale.
In A Room With a View, it appears that how a young lady of social standing is expected to behave is a force that others use to try and manipulate Lucy Honeychurch. Psychologically, she is under great pressure from a variety of people, most notably at the beginning of the story by Miss Bartlett, to conform and learn the ways and manners that will ensure that she "fits in." Note the way that she has given up swimming in the Sacred Lake and always tries to say and do the "right" thing. It is only at the end of the novel that she is able to break free from such pressures and influences and follow her heart's desire rather than her intellectual and rational thoughts by rejecting Cecil Vyse, the epitome of social manners, and marrying George Emerson instead.