How does Poe use tone, diction, etc. to create an overall effect upon the reader in "The Fall of the House of Usher"?

Poe does that by adopting the elements of Gothic literature which are a) descriptive language that target specific feelings of horror, coldness, fear, and nostalgia (especially nostalgia) in the reader,  b) the inclusion of the supernatural in the narrative,  c) the use of nature as a form of creating atmosphere (cold climate, overcast, shadowy, dark, wet, humid), d) the debate of normalcy (usually Gothic literature would exaggerate a character, or a situation to stimulate anxiety in the reader, for instance, the man Usher, his sister's disease, the house),   e) and the inclusion of death as the last resort.

The diction and combination of words are also a mechanism in Gothic literature as it appeals to the nostalgia from the reader, the use of proper, old English, the over-formation of words, etc. All those are typical mechanics of Gothic lit and House of Usher is a prime example of it.