1. Choose a poem that you have always admired or have one assigned to you at random (such as can be found at the following site)
2. Try to "copy" the style of the poem, including the type of observations the original author might make, the types of associations the author might make, length of line (rhymed?/unrhymed?), kinds of line breaks, level of sentence complexity, word choice,tone, possibly even subject matter (though the most interesting results are produced when the subject matter is completely different than the original poem).
3. Don't be afraid to get it wrong and let your own "style" creep in. Often this makes for interesting amalgamations.