You should aim to base your essay on context - as the module is on TRANSFORMATIONS. I agree with ^. Stick to a thematic approach (eg, the fashions and interests of society change, but human nature remains constant, themes which reflect human nature etc etc). So split up your essay into intro, body [social structure, importance of marriage, development of central heroine], conclusion.
Integrating irony - you'd be best off referring to the novel as an indictment upon society - Austen was critical of the rigid social structure of the day etc etc. Both Emma and Clueless represent microcosms of society. Example: "Sir Walter prepared with condescending bows for all the afflicted tenantry and cottagers who might have a hint to shew themselves."
Authorial intrusion - provides comic relief by exposing the difference between Emma's perceptions and reality "Emma had too much her own way ... disposition... too well of herself". So that falls into the theme of self development. (Both Emma and Cher are on journeys of self development).
Omniscient narrator - presents events from Emma's perspective as well as Austen's. Example: "She would notice her; she would improve her; she would detach her from her bad acquaintance and introduce her into good society" (upon 'improving' Harriet) - in showing Emma's thoughts, Austen reveals how self-deluded and presumptuous Emma is being. This gives us an insight into Emma's self development.