Another Hint

Okay, think of a minor character--Hindley, Isabella, Lockwood, Joseph--again, basically anyone not named Heathcliff or Catherine, you could say. Look at the way the minor characters are characterized against the main. The differences may illuminate the main character's strengths, flaws, weaknesses, desires...For example. Hindley torments Heathcliff, in large part because of a perceived status--Heathcliff has no name, no family history, a man without an identity. You could develop how that relationship(Hindley vs. Heathcliff) shaped the monsterous, relentless side of Heathcliff, meanwhile Hindley slowly and surely descended into a kind of nihilistic wastrel, dying broke and in obscurity. In general, for this kind of essay, we want to reveal, discuss, CHARACTER(in my example, Heathcliff's character) and looking at the relationship with a minor character, a foil, can just be another way of doing it. If "compare and contrast" seems a prompt you're more comfortable with, why, go with that.