Dolly Parton's song, "I Will Always Love You," uses some poetic devices; it would not, in my opinion, stand up very well as a written poem without Parton's unique singing talent.
The poem's meter is irregular, with lines of anywhere between 3 and 11 syllables.
The first 8 lines of the poem rhyme, albeit in an unusual rhyme scheme: aa ba cc dd (assuming that "memories," at the end of line 7, rhymes with "me" at the end of line 8).
There are no striking images in the song. "I'll think of you each step of my way" could cause one to imagine a despondent person walking along a road; most people, I would venture to say, simple take "each step of my way" as a commonplace expression meaning "all the time."
The repetition of the phrase "I will always love you" is a poetic device, but the phrase being repeated is hardly memorable.
If you really want to enjoy this song, watch and listen to Dolly Parton sing it, by following the link below.