We begin the term by tearing away clich s, clutter, wordiness, and by doing away with models that don't belong to the individuals. Then we work on various other aspects of students' work, in a group and individually. In fact, I teach stages of revision, helping the students to discover organization within their writing. I suggest that they start in the middle of a long essay, and write one chunk at a time. If you pre-plan too much, it takes the excitement and creativity out of writing.
Writing is an honest process of discovery.
The real time-taker is people staring at a blank page. It is psychologically much more healthy to take raw material and shape it, rather than aiming for the perfect sentence. The latter can be quite discouraging. The hardest is teaching students to trust themselves. They often feel if they try to write honestly, they'll be penalized.