How should I continue this essay?

For this question, I would definitely say you should talk about Poe's interest in detective fiction, which he actually originated in his stories of C Auguste Dupin. Also consider the strong interest of both writers in science and technology, and the fact that both were writers of stories that can be classified as early attempts at science fiction. I would put less focus on the Gothic and macabre elements of Poe's work because, although they are part of what he is famous for, they are the least similar to the interests and writings of Conan Doyle.