Interesting choice of texts to compare. You might want to analyse the concept of individualism in both of these texts and explore how this theme is presented. For example, Hemmingway's novel examiness the way in which World War I resulted in the death of loyalty to institutions and traditions that typically commanded great respect and obedience. The characters in this bleak novel deliberately are shown to eschew the demands of tradition, society and the various institutions that exist. Traditional moral viewpoints are rejected and the characters follow lives that are focussed on their own individual wants and desires. Consider Rinaldi, for example, who is focussed on being a better surgeon and being a better lover. When Frederic asks whether there is anything more to life than this, Rinaldi responds with a statement that makes clear how individualistic he has become: “We never get anything. We are born with all we have and we never learn. We never get anything new." This novel therefore paints a rather despairing picture of a humanity that has lost its moral compass, leaving its inhabitants to wonder around without the guidance of any higher morals.
"Barn Burning" takes a slightly different approach, as Sarty is challenged by the conflict of being true and honourable to his father, as tradition demands, but then the deeper conflict of doing what he thinks is right. The way that his father deliberately engages in acts of illegal arson brings this conflict to the fore. Note how Abner Snopes responds to Sarty's temptation to testify against his father during the trial at the beginning of the story:
You're getting to be a man. You got to learn. You got to learn to stick to your own blood or you ain't going to have any blood to stick to you.
The traditional concept of "sticking to your blood" and staying loyal to your family is thus balanced against Sarty's own feelings of what is right and wrong. He is forced by the end of the story to abandon family loyalty to follow what his higher sense of moral justice.
Thus both texts have a similarity in the way that they approach traditional morals and institutions such as the family. However, the characters in Hemmingway's classic seem to have forsaken any sense of tradition or right or wrong, whereas Sarty at least still clings on to some kind of understanding of an ultimate right and wrong.