Faces in the crowd

Any idea's on creating a poem which should include 4 metaphores, should not rhyme, including opposites and echoes.....with the focus being on powerful vocabulary!.....I am the mother of a child still at primary school who is trying to help with this weeks homework.....I'm 40 something and I am at a loss and am trying to be of some help......anyone able to help me? would be very much appreciated.