Antiphon's sorry that we don't give personal feedback on rejected work - there are just too many submissions. And if we just said a sentence or two, it might be misleading, and the poet would query it, and we'd get into a debate...
My best suggestion would be to consider this poem, Zen and the Art of Submitting Poetry, by Cameron Self
and if you want serious feedback, and are happy to join in workshopping others' poems (and learn lots by doing it), then join one of the excellent online poetry forums. I'm biased, but Poets' Graves is very good. It's an excellent way of exchanging thoughts with other poets and finding out what works and what doesn't.