Denise Levertov on revision
I might see that the punctuation isn't right, or the line break isn't quite right, or I may want to add or subtract something. If you copy something out by hand, before you move onto the typewriter, you've already gone on making minor changes. This is an intuitive part of the creative process, and one that's eliminated by the use of word processors. People get such a completed-looking copy that they think the poem is done. The word processor doesn't take as much time as actually forming the letters with your hand at the end of your arm which is attached to your body. It's a different kind of thing. They don't realize that this laborious process is part of the creative process.
I've been writing poetry for many, many decades. In talking about the process, I'm almost obliged to say, "First you do this. Then you do that. Then you stand back. Then you do that." But these things overlap and flow into each other. One has to use that linear description of a process that is actually much less linear, much more intuitive, doubling back on itself. But it's only for convenience sake that one has to talk about them as a sequence of discreet events, because they really aren't.
One has to have a good ear, but you also have to read what you're working on aloud. Even if you have a good inner ear there are certain awkwardnesses that only become apparent when you speak out loud. At some stage, you have to at least mutter to yourself. When I'm writing it out, I do a lot of muttering.
Yes, it's discovery, being attentive to the form that emerges. Critics always talk in such a deliberate way as if poets write with the same methodology that people write criticism. One doesn't write poetry that way, or fiction.
Some poems come into being and don't need revising. They emerge out of nowhere. You have to recognize they are complete and not mess around with them. This certainly doesn't happen with every poem. But you would be mistaken to suppose that every poem has to go through many revisions. You're bound to develop some craft confidence in all this after you've been doing it for a while.