Start writing poetry that you can submit to publishers. Create a writing schedule and be consistent about producing some poetry everyday. For example, commit to writing at least 30 lines of poetry daily; it doesn't have to be publishable, but it will hone your poetry skills.
Read as much poetry as you can in both online magazines and other sources. By reading diversely and critically, you'll increase both your knowledge of published poets and your chances of being a more confident and engaging poet yourself.
Conduct research about online poetry contests. Such contests are abundant and are often conducted by online magazines. Many ask for poems addressing a certain theme. Some require entry fees, which they use to pay the contest's judges.
Study the previous winners of contests. Remember that the best poems don't always win online contests. By reading the winning poems, you can gauge what impresses the judges and write your poems accordingly.