Thanks to Julie Ewald's blog, I found a great article on revising a poem: Sonya Feher's list of five strategies to take your writing from draft to poem. Revising is probably the most important factor in writing of any kind. I write for a living -- grant proposals, mailings, brochures, and other things to raise funds and awareness -- and write in my spare time too. I'm constantly up against my own word-blindness. It's natural to love your own work, especially just after it's flowed out into existence in words. What seems unnatural is to undo or redo the thing you loved into being. But it's what separates the good work from the amateur.
Another trick I find useful is to read a good poem that has some relationship to the one I'm working on. If I am working on a humorous poem, reading Elizabeth Bishop's "Filling Station" might help me revise mine. Or reading any good poetry and noticing what makes it good.
Unfortunately, you can't revise your way into greatness, but you can first-draft your way out of it, I do believe. Letting a poem remain in raw state is one of my cardinal sins. Revise, revise, and revise again! My editor, Bryan Roth, suggests giving a poem at least a year before even thinking it might be finished. He has a good saying to paste onto your computer: "Impatience is the enemy of good writing."