Wishes, Lies and Dreams by Kenneth Koch. Everywhere by Jack Collom and Sheryl Noethe. Try this poetry exercise from Matt Sharpe. Poetry is a great way for kids of any age to learn language. As far back as Aristotle, educational theorists have said that we learn more by doing stuff than by thinking about stuff.
Poetry engages language at the highest level.
You need to be grammatical and specific, you need to stretch your vocabulary, you need to engage the reader's five senses. You have to say in what way the building is beautiful. I was thinking. This works for kids, too. I encourage them to surprise themselves, to be silly, to express what's going on in their minds.