PART A:
The movement from a first draft to a middle draft is predicated entirely on focusing on major flaws. Think triage. Your job is to stop the bleeding where the bleeding is most profuse. Don't worry about hangnails. Here are the first places to look:
focusing the persona
focusing the "real subject": understanding how each section contributes to and deepens the readers sense of the essay's important concerns.
developing scenes: good narratives are usually built around long, rather than short, scenes
developing reflection/retrospection
developing characterization
Implicating the persona
Giving the persona (and all the main characters) choices--opportunities in the story to control their fate
providing all the basic orienting facts the reader needs to understand the characters and the story
ruthlessly cutting away all writing that doesn't contribute to the real subject
Don't mistake line-editing "polish" work for the hard work of the middle draft. The middle draft is about taking risks with your material, "killing your darlings," knocking out bearing walls. In the middle draft, you re-imagine your story, and it moves away, usually, from what you thought it was about, to what "it" wants to be about. The middle draft is about surrendering control to your story, being open to its dramatic possibilities. It should end up being very differently than you initially imagined it. It should surprise you, and this surprise, should, on some level, be difficult for you to accept and follow (at first). Experienced writers recognize this feeling of surprise and it tells them they're on to something. They're on the right track. No surprise for you, no surprise for the reader.
How to go about this hard middle draft work? By writing. Not by thinking. Thinking is not writing, but writing is a concentrated form of thinking. What to write about? Where to begin? With any of the major areas needing work that your first draft suggests to you.
The narrative persona should be focused, or limited. The persona is limited by its relationship to something else, something intrinsically interesting and larger than the self. Remember you are not a subject. You are not a story. You are a person. The story you are telling will become more and more clear, in focus, the more you refine this relationship. Baldwin's Notes of a Native Son is a story about a father-son relationship. Baldwin's persona, principally, is: the son of a father. Race and racism, of course, are incredibly important in the essay, but most important is this one limited persona. Think of all that Baldwin left out. He is not, in any important way, the son of a mother, nor is he a sibling.
Risk wisdom. Implicitly and explicitly, the real success of your work depends on your own ability to say something about your subject. What about father and son relationships? (Another way to say this is: what about what it's about?) We know the essay wants to be about a father-son relationship, but what insight organizes all this material. Every essay has as its object the attempt to say something universal from a dramatic set of particulars. This insight is what Gornick calls the "story" and what Hampl calls the "real subject." Many fine middle drafts in workshop are focused, tell a story with a beginning, middle, and end, but do not attempt this higher order of generosity--they don't yet step outside their limited set of particulars and speak to a general condition, to all of us. They don't yet attempt to give to the reader something they might need or use in their lives. What might be one way to get to this insight? Say the toughest thing.
Develop tension and conflict. Think about what you, as a narrator, want. Think about what is getting in the way of you getting what you want.
Make yourself vulnerable. Implicate yourself. Characters don’t become less sympathetic when they act badly; they become more sympathetic.
PART B:
All the while that you are writing, at any drafting stage, also think about these kinds of revisions below. (But not at the expense of the major changes above. Though, paradoxically, a small change can sometimes lead to a larger change.)
Make sure details are not only concrete but significant. (Tight blue jeans are concrete and specific, but unless they are significant, don’t mention them. The reader will clothe you. You won’t be naked.)
Comb out clichés and overly familiar turns of phrase.
Use figurative language: simile, metaphor, personification. Perhaps there is an extended metaphor that guides the entire essay.
Use precise active verbs (Do a verb check. Circle all the passive verbs, and try to make more than half of them active. She was sad becomes: Her shoulders sagged and she sighed.
Think about sentence variety for dramatic effect.
Use punctuation for emphasis! Don’t merely follow the rules. Use the rules to your advantage. Break rules! (Is that, then, a rule?) Italics? Capitalize? ME?
Pay attention, intuitively, to the music of your language. Read your work outloud to yourself. Read your work outloud to someone who will suffer you.
Weed out overstatement.
Try to move your reader, provoke them. (Scenes communicate emotion. Emotion, rendered as telling, often dies on the page.) But beware of the line between drama and melodrama. Try to get as close to the line as possible without falling over into “the depths of your soul.” Don’t assault the reader with the word “soul.”
Humor? Irony? Ever considered them?
Attempt to have your essay embody a wide range of emotional attitudes.
Make sure your themes are consistently developed.
Anticipate the skeptical reader who hasn’t a clue what you’re talking about, never seen the place, the person, you’re describing.
Tell the story in images. Make dramatic moments with scenes.
Think about the effect of your first sentence. Pull the reader in. Think about the resonance of your title.
Make sure you’ve proofread sufficiently and that there aren’t stray grammatical or mechanical errors that pull the reader out of the dream you’re creating for them.
Push yourself, stylistically, technically, to do something that you can’t do or haven’t tried: Scene. Dialogue. Figurative language. Take risks. Don’t rehearse your instincts.
Use dialogue to advance the conflict and to characterize.
Attempt to make each craft feature (narrative structure/imagery,etc) of your story speak to the deeper issues of the story.
Attempt to find a balance between showing and telling. Between scene and reflection. Write a scene and then reflect (perhaps as an adult intelligence looking back) on what this moment meant to you then and what it means to you now.
Feel enthusiastically dissatisfied and keep revising.