One means Elizabeth has of maintaining self-respect is by accepting and treating all situations with her sense of humor. We first observe her abilities to take insults lightly using her sense of humor when Darcy first insults her at the Meryton assembly in the beginning of the book. When Darcy insults Elizabeth by refusing to dance with her at Bingley's recommendation, saying, "She is not handsome enough to tempt me," Elizabeth's response is to laugh at him among her friends, relaying the story with, as Austen describes, a "playful disposition" because she enjoys "any thing ridiculous" (Ch. 3). What's more, her ability to laugh at others and at even her own insults shows us that she is very capable of maintaining her own dignity, pride, and self-respect.
We see a second example of Elizabeth maintaining her dignity and self-respect in the face of what she believes to be another insult while she stays at Netherfield during her sister's illness. At one point Miss Bingley starts playing Scottish music on the piano and Darcy turns to Elizabeth and asks if she would like to dance to the music. Elizabeth, having already judged his character to be excessively prideful and arrogant, believes he is only asking her that to gain the opportunity of insulting her again. Elizabeth responds by openly stating she recognizes his attempt to insult her taste in music and dancing and saying that she will tell him she does not want to dance in order to thwart his attempt, as we see in her lines:
You wanted me, I know, to say "Yes," that you might have the pleasure of despising my taste; but I always delight in overthrowing those kind of schemes, and cheating a person of their premeditated contempt. I have therefore made up my mind to tell you that I do not want to dance a reel at all--and now despise me if you dare. (Ch. 10)
Hence, we see that Elizabeth continually maintains her dignity and self-respect through her wit and humor.