In her blog Rocket Kids, poet Rachel Dacus talks about revision as re/vision, the process of seeing again:
"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."
She goes on to note "you can't revise your way into greatness, but you can first-draft your way out of it. "
She links to Sonya Fehér's guide to revision. Feher has a set of thoughs on how to revise a first draft--10 easy tips to revise your poems-- which focusses re-seeing the poem at the word by word and line by line level, doing things such as going through the poem to underline the concrete nouns and the strongest/most specific words, phrases and passages.
In her follow-up post, with thoughts on how to revise that draft into a poem--5 easy strategies to take your drafts to poems--she focusses more on the poem as a whole; the content, the mood, the pacing. She ends with a look at the soul of the poem. I heartily agree with her caution that "it is possible to wreck a poem with reworking it, to completely lose the greater meaning or feeling in quibbling over sound devices or an image." Over and over again, I've looked at a revision, and realized that, although the revised version is clearer, less awkward, and less reliant on received language and cliche, in the process of becoming polished it has lost something of the original raw spirit that energized the poem to make me want to write it in the first place. It's hard to reconcile, sometimes; there seems to be no middle ground between the embarassingly awkward rawness of the first draft and the clearer but less direct polished version. She recommends saving the drafts of every version, a wise move (although one that clutters up the desktop).
I don't know if there is a simple way to revise, any ten rules or five simple strategies. Revision is hard.
Necessary... but hard.