I'd recommend just heading over to your library or bookstore and browsing the poetry section. See what interests you and what you like.
Honestly I will say it is very hard to understand poetry (and that does definitely include myself most of the time!) It takes a lot of reading not just of the poems themselves but of the backgrounds of the authors, their life biographies, themes and a study of the different genres of poetry itself.
I'd suggest maybe getting an anthology first of a type of poetry you like... ie American poetry, modern poetry, Spanish poetry, English poets etc some will have commentaries that will help in understanding the poems as well.