Rachel Starr Thomson, homeschool grad and author of numerous books, has been tackling this question on her blog. I have been incredibly inspired and challenged by her thoughtful and practical advice on this topic. If you are interested in improving your writing skills, or learning how to help your students or children improve their writing skills, I highly recommend checking out the posts in the series thus far:
When Is Your Writing Good Enough, Part 1 – Introduction
When Is Your Writing Good Enough, Part 2 – Train Your Ear
When Is Your Writing Good Enough, Part 3 – Get an Education
When Is Your Writing Good Enough, Part 4 – What Other People Say