Mrs. Dalloway is the perfect hostess, at least that is her goal. She struggles though with the desire of "self." She wants to be more isolated and she is an individual mind in a time with there is a lack of individuality. Woolf has drawn a character full of self doubt and although she comes across as a total woman and hostess she is filled with the uncertainty of her decisions and her lifestyle.
A good way to deal with the theme of doubt in Woolf's "Mrs. Dalloway," would be to dwell on the main character. Most of the story is from her point of view so it would be beneficial for you to peel away the layers of this "party diva" and look beneath her surface for the doubt of the individual.
"She sees Peter Walsh, who has returned from India, and drops in for a visit. This meeting, and many other moments in the day, make Clarissa think about the past and the choices she has made."