The primary difference between poetry and prose is that poetry is generally written using a particular rhythm while prose is written more closely to natural speech. Poetry is more structured and is often arranged in clear lines which fit into a certain pattern. It also commonly rhymes, while prose does not.
A structured form of writing is the main difference between poetry and prose. Although most forms of writing typically make use of literary elements like alliteration or narration, poetry is constructed from one of various structures, including alternating rhyming and non-rhyming verses. Even free verse poetry, which does not usually rhyme, fit into some form or structure.
Both poetry and prose are generally creative in nature and are used to express emotion or to tell a story. Although poetry is more structured in terms of the format in which it is written, prose is generally more rigid in terms of grammatical correctness. Prose is typically comprised of complete sentences which convey specific thoughts or feelings. Poetry is often more abstract or vague with words being written as they come and less attention being given to proper grammatical rules.
Prose is the form of writing most commonly associated with novels and creative nonfiction works. It still may follow certain rhythms and cadence in the way the words flow, but it is less rigid in nature. Long sentences are often followed by shorter or choppier ones for dramatic effect. Prose may also combine the use of narration and dialogue, or speaking between two characters. This is not to say poetry cannot tell a story, but it is often less detailed.
Although both poetry and prose are an art form, some would say that prose is more difficult to write effectively. Since many forms of poetry lack the typical rules required of most forms of word composition, there is no right or wrong way to write a poem. Some poems obviously have more emotional impact than others, but it is harder to gauge a poem's correctness than with other forms of creative writing, since there are no clear-cut rules to follow.
Poems often make use of the sounds a word makes combined with literal meaning. Poetry is often written in symbolic language, while prose is typically more literal in nature. As with all creative arts, the exact way in which either form is written has more to do with the individual writer rather than rules and restrictions. Writing is not an exact science in terms of creative expression. While the rules of grammar should be followed for clarity, the flow and cadence of a work may vary from story to story, with one not necessarily being greater than the other.