In responding to a friend who asked recently, I present my answer to the question, “What is a poem made of?”
Poetry is language defined by compression, saying more with less. It is language meant to be read out loud, slowly. Language in a poem plays with sound. Poetic fluency is likely hardest to quantify, but it comes from a blending of sounds (repetitions and rhythms).
A poem is essentially figurative, with some aspect of metaphor at its heart. But a poem can be a painting, too, as haiku often are, an image of a moment seemingly frozen in time.
To me, all poems tell stories, but sometimes just an edge of a story. At the end of a poem, there should be a surprise, a notion not before considered, or at least not considered in the same way.