I was checking out a favorite blog, Critical Mass, a blog devoted to education. The question arose, how should writing be taught to ensure that students will become competent writers?
My belief, based on my experiences, is that nothing beats practice, practice, practice. You have to slog through the process of assigning the initial writing, marking it for errors, and helping students go through the correction and re-writing process.
It takes time. It takes effort. It takes some knowledge of the English language.
I have a small suggestion how teachers whose subject matter isn't English might approach the matter. Make an agreement that, each week, you will assign a short essay (3-5 paragraphs). You will provide the expertise about your subject (including spelling and usage), but the English teacher will correct for syntax, organization, and the like. If you share the load, students could get credit for both classes.
Too many students dash off the first draft, and assume that one pass at the assignment is sufficient. The essence of writing is re-writing.