Stylistically, Edgar Allan Poe's stories and poems are characterized by elements we might now associate with the horror and gothic genres. There is usually suspense, created in part by an unreliable first person narrator, and there is also often a supernatural presence. Poe also often relies on dark, sinister settings, and macabre imagery.
His poem "The Raven" demonstrates most of these stylistic elements. For example, the poem begins "Once upon a midnight dreary," and later we are told that it is set "in the bleak December." There is also a fire which casts ghostly shadows upon the floor. This is a typical Poe setting. It is dark, shadowy and implicitly hopeless. There is also suspense in the poem because we, and also the narrator, don't know why the raven haunts and taunts the narrator. The raven also seems supernatural, and the narrator is convinced that it is a "thing of evil" with eyes that "have all the seeming of a demon's." The poem is also full of macabre imagery. As well as the "Ghastly grim and ancient raven," there are also images of "tempest(s)," "fantastic terrors," and the "Night's Plutonian shore." There is also of course the recurring image of the narrator's "lost Lenore," which constantly reminds us of her death.
Poe's short story "The Tell-Tale Heart" is also a good example of many of the aforementioned stylistic elements. The narrator is obviously, from the beginning, quite mad, and certainly unreliable, even though he insists that his madness is a "disease [which has] sharpened [his] senses," rather than dulled them. There is also in this story lots of macabre imagery, most notably perhaps the beating heart beneath the floorboards, but also the dismembered corpse of the old man. There is also plenty of suspense, as the reader wonders throughout the story whether the narrator will get away with the murder he has committed. As for the setting, this too is dark and gothic. The grisly murder takes place "at the dead hour of the night," and at the end of the story the narrator and the police officers sit "upon the very spot beneath which repose(s) the corpse of the victim."