Poe begins the story with a cumulative sentence. The independent clause “I had been passing alone,” has two modifiers before and after, followed by a conjunction that connects to a secondary verb (“found”) that also contains three modifiers. This underscores the pervasiveness of the “gloom” the narrator describes upon first seeing the house. This sentence linguistically envelops the actions of the narrator within the setting just as he feels psychologically enveloped.

Another rhetorical strategy used in the introduction is asyndeton. This is defined as the absence of a conjunction in a list of words. This is used in the following quote: “iciness, a sinking, a sickening of the heart.” The successive commas without a conjunction gives the feeling of endless stress that the narrator experiences because of the house. Without “and” this phrase is rhythmic and emphasizes the relentless nature of the speaker’s unease.

These are just two more concrete examples of rhetorical strategies that Poe uses in the introductory paragraph of the story.

Poe uses a first-person point of view. The narrator is an outsider who has never visited the house of Usher, and although an old school friend of Roderick Usher, he hasn't seen him in years. Poe employs two rhetorical strategies here: first, the narrator is viewing the scene with fresh eyes, so he registers all the shock of someone arriving this bleak setting for the first time. We feel his feelings. Second, because this is first person, there is no "pulling back" from the intensity of what is witnessed to a neutral, reassuring third-person narrative telling us what is "really" going on. We are up close and personal with the narrator, wondering with him about this dreary, eerie setting.

The opening scene of the narrator's arrival at this ancient home also alludes to a scene in Mrs. Radcliffe's The Mysteries of Udolpho, echoing the heroine's arrival at the creepy and isolated castle of Udolpho. This is not a familiar allusion to us; however, it would have been to Poe's audience. It would have worked rhetorically to persuade the readers that something unnerving is about to happen.

Poe uses punning to reinforce the connection of the house of Usher as a physical building to the house of Usher as the family line, an association that will become important later in the story.

The opening is marked as well by relentlessly bleak language: everything is melancholy, dreary, depressing, and gloomy. This language is so unrelieved as to be oppressive and makes the reader feel the oppression that the narrator experiences. As he puts it:

There was an iciness, a sinking, a sickening of the heart—an unredeemed dreariness of thought which no goading of the imagination could torture into aught of the sublime.

The sublime is that mix of awe and grandeur in a landscape that uplifts and frightens us at the same time. Here, there is no uplift, foreshadowing the grim tale that is to come.

He uses sound, especially alliteration:  dull, dark, dreary, desolate, decayed depression, dreariness--and this is just paragraph one.

He uses punctuation as a rhetorical strategy: in paragraph two the narrator frequently breaks us his speech, which the text signifies through the dash (--) to indicate his fragmented thoughts brought about by what he sees, the House of Usher.

He uses personification, referring to "eye-windows" twice in paragraph one.

He uses sensory images repeatedly to create mood: the day is "soundless," the trunks of the trees are "white," and there is an "iciness" about him.

He uses analogy: he feels a depression somewhat like the "after-dream" of opium; "it is like "the hideous dropping off of the veil." 

One for good luck:  he uses metaphor in paragraph two when he says "it was the apparent heart of the request."