Bring a notebook and pad everywhere. Engage with the world and observe closely. Write down images and thoughts as they occur to you. Don't edit yourself, just get the words down on paper. Later, go back and sift through these fragments and scribbled lines. Look for connections, look for clues. What appears to be trying to emerge from the rubble? What does your subconscious want to say? More than likely, you'll be surprised at what you find.
Often, a well-chosen image or phrase can be enough to unlock a writer's mind, allowing it to run free. Consider choosing an unsettling image from a favorite poem and crafting a response to it. Alternately, use a poetry prompt to get yourself started. Write a poem about the passage of time, an adolescent memory, jealousy, a private wish, a secret grief, becoming a parent, losing a child, a time you felt invisible, a time you wished you were invisible, or something you view as beautiful that everyone else overlooks.
To a great extent, the success of a poem depends on the reader's experience of it. Ted Kooser, former United States Poet Laureate, writes, "Poetry's purpose is to reach other people and touch their hearts." Poetry is communication. Picture who you're writing to, whether it's an imagined ideal reader or an actual person in your life. Hold him in your mind's eye as you write, taking care to keep your images specific and your prose free of clutter, so your reader can understand what you want to convey.
The bulk of a writer's education stems from her reading and writing. Because exercises and prompts can only take you so far, it's critical to routinely explore new poems and study how they're made. Read everything from sonnets to prose poems. Look at structure, listen for rhythm, observe how the poem works on you. Likewise, a writer must write. It's not enough to wait until inspiration decides to rear its head. Think of your muse as a wild animal you must patiently coax out of the woods. A daily routine of placing yourself at your desk, pen in hand, can be the most important technique for writing poetry of all.