What stylistic devices characterize the film? How is space used? How is the film edited? Note the extensive use of sequence shots and deep focus space. Note also the lighting, and the fluidly moving camera in many scenes. How does the style of this film relate to that of Citizen Kane? In what ways are these stylistic devices particularly suited to the story Welles is telling here?
Remember that the film as we see it now is only a mutilated version of the film Welles originally shot and edited. Among other things, it was reduced in length from well over two hours to under an hour and a half, and a new, happier ending was tacked on. (A list of all the cuts and changes between the script that Welles shot and the film as we have it now can be found here). One result of all the cutting is that the film seems rather choppy, with large leaps in time, and gaps in continuity. Still, there is a restraint and understatement to many of the scenes which is part of Welles' design. Think about the narrative economy of many sections of the film, like the funeral of Wilbur Minafer (in which the coffin is never shown). What other sections of the film similarly convey important actions economically and indirectly?
Consider how the film works both as a multiple character study and as a portrayal of social history. In terms of character, think about the arrogance and immaturity of George, the quasi-incestuous relationship between George and his mother Isabel, the numerous examples of baffled and repressed passion scattered throughout the film (that between Morgan and Isabel, that of Fanny for Morgan, perhaps that of Lucy--to a certain extent--for George), and the vignettes in which the passion of a character is suddenly revealed (such as the scene where we see the elder Major Amberson, near death and senile, sitting in a chair facing the camera, with firelight reflected on his face). In terms of social history, Welles' scenes going into detail about the gradual diminishment of the Amberson fortune were mostly cut, but you can still consider the remnants of what was meant to be an epic look at the fall of old money and the rise of new money, and at the way automobiles and their surrounding industries changed the face of American cities.