How does the story Pride and Prejudice develop?
One option is to review what happens in each chapter and summarize it in a paragraph or less. This will give you notes from which you can draw or graph a story-line.
Basically, the story develops as Elizabeth, who is the narrator, encounters various characters who impact both her and her family.
There are several threads to this particular novel. The main plot-line concerns the change that occurs in both Mr. Darcy and Elizabeth as they gradually get to know each other. Other plot-lines include the rest of the sisters and how all of the women are dependent on marriage.
However, also important to story development is the setting -- town or country, indoors or outdoors. Setting indicates how the characters may or may not behave as well as revealing personality traits.
Themes also play an important part. Love and marriage are front and center, but also important are freedom of choice, family loyalty and influences, gender equality, real friendship between men and women, integrity, responsibility, patience and, of course, pride and prejudice!
Once you decide what you'd like to focus on, whether it's how the story develops through the character(s), setting, themes or plot-line, you'll have a better idea of how to answer the question.