This question opens a whole can of worms if one ever did! Sheesh! There're probably as many answers as there are poets--or more. If you're asking specifically about form, here's something from Ezra Pound that may help. He identified two forms: "fluid" and "solid," saying that some poems "may have form as a tree has form, some as water poured into a vase." The book I'm pulling this from (don't even think for a moment I carry this stuff around in my own pure brain!) says "Fluid (or open) form is organic, like a tree's growth. Solid (or closed) form is symmetrical, like water poured into a vase. Both are natural, and so long as the poet is willing not to be theory-bound, he or she may use whichever a given poem wants." (Writing Poems, Robert Wallace) I'd agree with tjames and tresamie that if and what the poem communicates is the most important thing to consider. That being a given, I think the way the poem lies on the page and rhythm and rhyme (or lack thereof) are also pretty important, because these things are part of the communication. You can put a lot of atmosphere/mood/emotion into a poem with these things without ever having to state them outright. (For instance, the slow-motion feeling in your April Fool's poem that came from the structure.) I think I'm rambling. :o And this is just my own opinion, of course. (Even if I am rather fond of it. ;)) Lu