Write a poem addressed to some animal, object, place, or maybe even to a person, whom you don't know or don't expect to read this. You could write to your cat, to a lemon, to a cutthroat trout, to Madonna, to Martha Stewart, to the Empire State Building, or . . ..
This sort of poem is called an apostrophe. William Blake's "The Tyger" and Walt Whitman's "To a Locomotive in Winter" are examples, as is John Keats's "Bright star, would I were stedfast," which is also a one-sentence poem.
If you like, you could follow Blake's example by composing your poem entirely of questions. Keep your poem between six and sixteen lines long.