I'll try to give a different answer from the others (although they're all good).
Before writing poetry, start reading poetry (and listening to it!). The point isn't to be able to define what a sonnet is vs a tanka but rather to get a feel for a style (and everyone has one), themes and techniques that "talk" to you. Then you can seek out well-known poets who have really mastered those. If you are a podcast sort of person, I would highly reccommend listening one of the various Poetry Foundation series (my favorite is "Essential American Poets").
Then just write...ok, not *just* write. Have a purpose: an idea, message, emotion, picture...something that you want to get across and make gettting it across as vividly as you can your mission. And just focus on one idea...more than that is hard for you or the eventual reader to really focus on. One's plenty. ;-)
Last: write regularly. Every day if you can. Writing is like anything else: natural talent aside, if you want to develop the skill, you need to work at it. Don't be afraid to write "bad poetry"...every poet on Earth does. In fact, I find writing bad poetry really helps the creative process...clears your system, sort of speak. As Bukowski once wrote, he liked to reward himself with a "candy-ass poem" after being particularly productive. ;-)
Good luck! :-)