Go in the back door when teaching writing. Let confidence build through constant encouragement of effort, improve ment, constantly pointing out the good, the progress. Then, point out the mechanics. As Edward Albee said in Zoo Story "Sometimes you go a great distance out of your way to come back a short distance correctly."
People do not think in a linear fashion, ABCD or 1234. We think more like spirals; "When I was four...and then when I was fifteen...and yesterday...and back when I was four..." Read The Education of Little Tree "...to feed a hungry man is good, but to teach him to fish is better."
Editing, rewriting, correcting is the fun part, the easy part. The hard part, the first part, is getting the first thoughts down on paper, or into the computer, any way at all, just recorded, out, visible, physical, set down on paper. One preference is pen on paper because it's so physical, so active, and writing is such an active process. The muscle in the forearm strains, and though it frustrates and gives pause, the pain shows the muscle is used.