(Because, yes, my rules go to eleven. Don’t yours?)
Do not render any absolute judgment on your paragraphs. At most once a week, simply rank them from best to worst.
In the moment, while writing, simply do your best. Do your best, given the difficulty of the subject and the state of your game. Don’t try to be a better writer than you are capable of being, but do try to be the best writer you can be today. Since you are in fact writing, it is nonsense to say you can’t write. It’s also nonsense to say you can’t write well. (“The cat is on the mat,” is a perfectly well-written sentence. Don’t tell me you are incapable of composing it or any number of sentences like it.) What you are experiencing is a particular difficulty in writing about some particular thing. Face it squarely. Bring your ability to write to bear on it. Don’t indulge your feeling of incompetence.
When the 27 minutes are up, take your three-minute break. Do not read over what you have done. Put it behind you and move on to the next paragraph or the next thing on your list of things to do. Don’t even ask yourself whether what you have done is any good. Why think your judgment now will be any better than your writing just was? (How often have you reread something you thought was brilliant a few days later, only to discover it is rambling nonsense? How often have you been pleasantly surprised by the result of what, at the time, seemed like a futile struggle to be precise?) Your feelings about what sort of quality you produced is biased by your immediate subjective experience–by how you felt today, by how hard it seemed–and you don’t have time to be objective about it any longer. Forget about this paragraph. You did the best you could. The paragraph will not improve because you are thinking about it. It will improve the next time you write it. And before you get back to this one you’ve got other paragraphs to write.
At most once week, take some time to read over what you have done. Gather up ten or twenty paragraphs and read them, one minute at a time. Don’t read them out loud this time, just read like you would ordinarily read the work of someone else. Give the first paragraph a score of 50. Not a score out of 50. Just give it 50 points for being what it is. After reading the next paragraph (taking no more than a minute, remember) give it a score relative to that. Keep going for the 15 or 20 twenty minutes it takes to read your paragraphs. You’ve now got a sample of your work rated from best to worst. Spend another 30 minutes or so thinking about what it was that made some of the paragraphs better than the others. What caused you to give them more points than the first one? What caused you to give them less? What are you doing right? What mistakes do you seem to keep making?
Other than typos and minor corrections, do not get bogged down in editing your text. You are trying to experience your own standards. The only way to actually live up to those standards is to do the work in a properly planned writing moment. Contrary to myth, good writing is not produced by editing. It is produced by rewriting. The difference is important.
During the eight weeks you are training, don’t try to decide whether any particular paragraph is “good” or “bad”. It is always merely and inexorably an example of something you can do better. Bad writing is not something you avoid, it’s something you try not to do. Your writing isn’t bad when you’re not doing it. It’s not lying there on your hard drive being bad. If you want good writing go and do some. Don’t try to “fix” some piece of poor writing from the past.