Would you say that this paragraph conveys my main idea well/is cohesive?
The main characters in The Autobiography of an Ex-colored Man and The Great Gatsby relate most closely in that they use deceptive identities to safeguard themselves from the prejudices and biases of others. These main characters implement facades of appearance for the ultimate purpose of breaking barriers of prejudice and fulfilling their dreams. Upon applying these alternate personalities, both Gatsby and the narrator from The Autobiography of an Ex-Colored Man prove that perception by stereotype does not reveal a personís true personality, and furthermore, leads one astray by enticing him to pursue unattainable dreams, stained by the looming peril of failure.
I'd say that the characters 'resemble each other' rather than relate. I'd also change the pronoun 'him' at the end to 'one' to keep the pattern. Can one 'apply' an 'alternate personaility'? I'd suggest using 'adopt'.