Almost all of Frank O'Hara's poems are written in free verse, meaning that they have no rhyme scheme and no formal meter. So, what makes an O'Hara poem an O'Hara poem?
Poetry critics have come up with a great formal categorization for "Poem [Lana Turner has collapsed!]" and others like it. They call these poems O'Hara's "I do this, I do that" poems. (Really. That's what they're called.)
Why, you ask? Well, a lot of O'Hara's poems, including this one, are seemingly casual narratives of his day. His speakers walk down the street, have a Coke, look at the newsstand, stop by to see some friends, buy some poetry, and so on. They do this. They do that. The speaker of "Poem [Lana Turner has collapsed!]" is no different.
While it has no formal pattern, the "I do this, I do that" style is signature O'Hara. His poems may not be held together by iambic pentameter or rhyme, but they are often organized by a loose narrative of personal experience that usually begins with the speaker walking down the streets of New York – doing this, doing that.