This is a really insightful article on revision. Here’s an excerpt:

How Poet Laureate Natasha Trethewey Wrote Her Father’s ‘Elegy’

By Alex Hoyt

Now, the reader seeing the final draft doesn’t know that I have my own secret journal in which I feel “silenced” by my father. The work of the poem is following certain paths and not others. I have to decide whether or not I’m going to reveal to an audience this side of my relationship with my father. When I write notes in my journal, I’m just trying to scribble down as much as possible. Later on I decide whether to follow some of those first impressions or whether to abandon them.

Writing [by hand] frees up a mode of thinking that allows me to consider more things without censorship, the way I would censor if I were typing. If I start writing on a computer, I feel that it’s official. When I’m actually writing by hand, I get more of a sense of the rhythm of sentences, of syntax. The switch to the computer is when I actually start thinking about lines. That’s the workhorse part. At that point, I’m being more mathematical about putting the poem on the page and less intuitive about the rhythm of the syntax.