We have had a spate of poems submitted recently, several of which followed no structure whatsoever - no divisions between stanzas, no punctuation, just long blocks of text. That makes the poem very hard to read and it doesn't flow as it should.
This is a great site explaining Poem Structure - Lines and Stanzas
This is a good reference site on all things poetry: http://www.poetrymagic.co.uk/approaches.html
Wikipedia's entry is very detailed too and tackles it from a more academic view: http://en.wikipedia.org/wiki/Poetry
If you have any bookmarks you'd like to share for our budding poets, please post them here.
Matriarch