Every great essay starts with a great brainstorm. Before trying to compare and contrast your two subjects, begin by writing down every bit of knowledge you have on the two off the bat, being sure that you are keeping the two subjects separate from each other for now. What is it that you already know about your subjects? What are you going to need to research further? Now take a look at the two lists you have made. The differences are probably fairly obvious, but can you pick out any similarities? If not, you’ll have to dig a little deeper.