big question: What are their particular situations? This is pretty much summed up by first line of each poem.
Devices: rhyme scheme, imagery, allusion, assonance
Organization: One body paragraph about the rhyme scheme/structure, one about imagery
Intro: talk about life
Thesis: Both authors use their poems to express their growing insecurity about growing older, and the associated consequences.
Body Paragraph 1: While both authors are attempting to prove the same point, each one uses slightly different methods. While Keats uses a regular ABAB rhyme scheme, Longfellow uses an irregular, unpredictable rhyme scheme. This shows how the speaker in Keat’s poem may have a more stable mentality than that of Longfellow’s. (cite a few lines containing rhyme scheme from each poem)….blah blah blah….blah blah
Body Paragraph 2: While both authors seem to be in despair, neither are short of energy to describe their despair in the most extravagant of ways. While Keats uses less potent imagery (“Hold like rich garners the full ripened grain”), Longfellow uses more obvious imagery to describe his disdain ( “A city in the twilight dim and vast, With smoking roofs, soft bells, and gleaming lights,—And hear above me on the autumnal blast”)….blah blah blah…blah blah.
Conclusion: blah blah blah…imagery/structure good….authors sad….ta dah! Done.