Think about an event or experience you are passionate about or brings about a lot of emotion. Your best writing will come from events, experiences and knowledge you are passionate about.
Write down keywords that describe this emotion. Look in your thesaurus to come up with descriptive and more lyrical words.
Write an outline of your poem by creating a story line of the subject of your poem. Each line should be describing the emotion as you felt it. You want the reader to feel through your words what you were feeling at the time. Incorporate words from the list that you created.
Transform the story line into verse. Creating a meter can help the reader feel the tone; each line will have the same number of syllables or there will be a prescribed line length. Walt Whitman style poems do not all have a set meter and in some of his works he writes in free verse. Having a meter is not required but is a tool that you can use to convey emotion, as Walt Whitman does.
Edit your work. Read it out loud to hear if you have incorporated the correct meter, if you chose to have one. There is no right or wrong meter, but reading your poem out loud will ensure you are consistent with the one you have chosen. Change around wording and descriptions to make the emotion even more intense.