I have always liked Lucille Clifton's poetry. Many of her pieces, including this poem "We and They," have a strong note of playful optimism.
One literary technique that she uses in this poem is rhyme. The poem is free verse, which means that it doesn't use regular rhyme, but there are more than a few repeated sounds, including "Sue" and "too" or "they" and "day" or "done" and "one."
A second literary technique is imagery. Many of the lines in the poem create a visual image in the reader's mind. The images are not extensively developed, but they're there.
A third literary technique is metaphor. Some of phrases don't make complete sense when viewed literally, such as "the night of the long bad dream," "'we' and 'they' is just a game," and "the wind is a friend." You might call that third item personification, if you prefer, but I think metaphor works there, too.