Poe doesn't have a lot of writing space to tell us about his main character, so he gets right to the point. The first two paragraphs tell us about the narrator's history, personality, hobbies, family life and reasons for going to sea. He's breaking the show-don't-tell rule, sure, but it gets the job done.
The story doesn't feature much in the way of dialogue, but with a first-person narrator in place, every word reflects his personality and character, especially when he compares himself to other characters as in, "Superstitious terror crept by degrees into the spirit of the old Swede, and my own soul was wrapped up in silent wonder" (8). He speaks clinically and with great detail, focusing on the landscape, the ships, the surroundings and the overall mood. From his descriptions, we sense his scientific mind, and an emphasis on getting the facts right… even if said facts are the stuff of summer blockbuster fantasy movies.
The location itself often reflects the narrator's state of mind, and hands us a few clues as to who and what he is. In the early scenes, the seas surrounding his boat are calm ("a more entire calm it is impossible to conceive" ), but as the story continues, they become wilder and more erratic ("the swelling of the black stupendous seas became more dismally appalling." ). The hurricane wind, icebergs and rolling black waves reflect his state of mind as he grows more agitated and afraid.