Each publication includes submission guidelines for poetry written by teens. Depending on the publication, this may include a main subject or topic to write about, or a certain style or form. Publications usually list contest guidelines on their website. Read through the entry rules and make sure your poem fits the necessary criteria, and check to see if an entry fee is required (though this is not common for teen poetry contests).
Write in a style suitable to your own voice, keeping in mind the submission guidelines. Keep in mind the different poetry formats--free verse, rhyme, and sonnets, to name a few. Publications accept many types of poetry styles, but submitting a poem that does not follow submission guidelines will result in rejection. The most common forms for teen poetry writing contests are free verse, where there are few literary rules to follow, and a basic rhyme scheme (four line stanzas or paragraphs, with every other line rhyming, for example).
Teen poem contests encourage a new generation to write and create, offering a chance to explore the literary world of poetry in a time when poems are difficult to publish, and when poetry read in schools is not contemporary or modern. Instead of going back to older poets and poems, publications create a forum where new styles can be brought to life, and young writers receive a chance to experience life as a creative artist.
Editors, poets, and other writers judge entries based on certain criteria, first of all considering if the poem followed the submission guidelines. After that, style, verse, and form are looked at carefully, though the most important aspect that judges look for is content and creativity--did the poem have a clear meaning, was the voice unique and was the writing expressive? Participants are notified if their poems won and when they will be published.
Inspect and research the magazine or publication that is offering a teen poem contest to avoid a money scam. If entry fees are involved, they are generally less than fifteen dollars, and try to avoid contests which require you to buy the book that published your entry. Reputable publications list all of their criteria up-front, and there should be no surprises.