In Emily Dickinson's "Because I could not stop for Death," there are several poetic devices used.
It should be noted that poetry is written to be read aloud. It is when we hear a poem that its musical qualities can be measured, as they resonate in our ears.
The first and most obvious literary device is the personification of "Death." Personification gives human characteristics to non-human things. Death is not a person; it has no personality. In this poem, however, it is spoken of as such; for example, it drives, and is not simply a state of being.
"Gazing Grain" is also an example of personification. Grain cannot gaze.
Another device used is alliteration. This is the repetition of the same consonant sound found at the beginning of a group of words. Note the author's use of "labor" and "leisure;" Recess" and "Ring;" "Gazing Grain;" "Setting Sun;" "Gossamer" and "Gown; and, "Tippet" and "Tulle."
Assonance is also used, once more appealing to the sense of sound. It is defined as the repetition of vowel sounds in a group of words. We hear it in "Gazing Grain" with the long "a" sound, and "Dews drew" with the repetition of the long "u" sound.
Another device that is used is meter, or rhythm. More than anything else, the poem's meter is iambic. This means that there is a stress on every other syllable. The point to this kind of rhythm is that as it is read, it feels as if there is a sway or lilt to the poem's movement. This is symbolic of the swaying one would experience when riding in a carriage, as it moves from side-to-side. This makes the poetic experience more realistic for the listener.
Finally, the poem's imagery is impressive. If we are not already impressed and affected by the sounds and the poem's movement, Dickinson's imagery cannot be overstated as an important element, especially in this piece—as the speaker describes the last things in the world that she either sees or recalls.
In the first two lines is the unlikely image of "Death" being "kind." We can imagine a sense of verbal irony here: we might not choose to stop for something; certainly we make many such choices daily in exercising our free will. In this case, there is no choice, and there is no kindness present at all.
Consider "We drove slowly—He knew no haste." In this image, we are confronted with one of life's greatest truths. When one is dead, time becomes meaningless.
We passed the Fields of Gazing Grain –
We passed the Setting Sun –
These two lines bring to mind a drive through the countryside, with grain that is unmoving (as is one who is "gazing"), and the colored sky hinting at a soon-to-come sunset.
Art speaks to people in many different ways—for me, the image I have is an orange cast to the sky that changes the color of the golden grain ever so slightly. These lines can also be seen as symbolic of the end of the speaker's last day—her last glimpse or the last moments of life; the transition between the living grain soon to be harvested, alive no more, as is the case with the sun setting, having ended its life...but only for another day.
Dickinson's mastery of poetic devices in sound and diction (word choice) allow the reader to travel with her and experience life as she once did—catching onto the kite tails of her imagination so we might see the world through her eyes for a short time.