Heya, is this for homework or an essay? That's absolutely fine! But knowing that helps us help you more effectively.

I would heartily recommend "For Cause and Comrades: Why Men Fought in the Civil War" by James McPherson. It is an excellent window into the minds of the men on both sides, so I think should help to provide you with a good understanding of the differences (and similarities of course) of North and South.

I would also recommend "The Shaping of Southern Culture: Honor, Grace, and War, 1760s-1890s" by Bertram Wyatt-Brown. It is only about the South, so won't provide much contrast, but it is a great look at the culture of the South in the period, and several of the chapters discuss the direct relevance to the Civil War, and the impact that that culture had on the direction. Hope that helps, and good luck with the project.