Try to write paragraphs, I always say, of at least six sentences and at most two-hundred words in exactly twenty-seven minutes. Please don’t feel this immediately as a constraint. Think of it like walking into a room that is just the right size for you to do a particular thing. It should feel safe and at the same time liberating. Some people, after all, set minimums only. They resolve to write at least 500 words a day, or to work for at least an hour. Others work to a “maximum” in the sense of trying merely to reach a goal. So they’ll write 1000 words or keep at it for two hours, sometimes using both goals and stopping when they reach the first. To my mind, this is a terribly imprecise way of organizing your work. My approach may seem more rigid, but is in fact very flexible. Crucially, it provides you with an ordinary, workaday sense of success and failure.
You decide in advance what you are going to say, i.e., what the key sentence of the paragraph is, and when you are going to say it, i.e., when the 27 minutes are going to start. Now, since the minimum is six sentences, your first problem is to find five things to say that support the claim in your key sentence. Once you’ve written six sentences your writing problem changes. You are now thinking more in terms of the quality of your argument than the mere quantity of your sentences. Improving the argument from here on might involve writing more sentences, but does not, formally speaking, require it. When (if) you reach 200 words the problem changes again. You now know your paragraph is probably getting too long and you have to ask yourself why. Did you subtly introduce a new topic? Are you repeating yourself? Are you just needlessly verbose?
Now, it is of course possible that you fail to keep within the minimum and maximum bounds. (Academic writing is not like one of those ridiculous businesses where, at least in the fictional universe of their advertising campaigns, “failure is not an option”.) But you only know you have failed because you have run out of time. Obviously, having written four sentences after five minutes is not failure. Nor is a 220 word chunk of prose at the 15-minute mark. And by similar logic, you haven’t succeeded when you’ve written 9 sentences using 176 words after 22 minutes. Anything could still happen! You could impulsively delete 5 sentences in the twenty-fifth minute. You could certainly find yourself writing another fifty words. You do have the option to sit still for five minutes, neither adding nor deleting, just reading the paragraph. But you have to keep at it.
The 27-minute “exactum”, which is a word I apparently have had to coin for this purpose, keeps the process centered, grounded, anchored. Pick your metaphor. It gives the experience of writing a small sense of its Sisyphean fate. It prevents you from “just getting it over with”. You start “in the middle” with a resolve to write for exactly 27 minutes. At the lower limit you have to write six sentences. At the upper limit you must stay within 200 words. That’s the nature of the problem. Defined in its finitude.
I also recommend you do your feedback this way. Here it’s important to set a specific amount of time, like 9 minutes, that stands in some meaningful proportion to the amount of time spent writing. Stick to it exactly. That is, let the person who is giving you feedback sit and think in silence as long as they need, but if the time runs out, that’s it. The feedback was that the reader couldn’t think of anything to say. In any case, it’s much easier to experience the (mild) discomfort of criticism if you know it will stop at a certain time, rather than when the critic runs out of ammunition.