She only had to write two paragraphs (rather than expecting herself to do more - athough she could - just that two was all she expected of herself each day) and they did not need to be perfect.
I heard her say it many times and she is quoted in another book on writing by a different one of college profs and I was trying to remember the exact wording but probably did not and at the moment I am not near my bookshelf to look it up. The advice has helped me write.