Teach students to prepare for writing by using graphic organizers like clusters, spider maps and Venn diagrams. Encourage students to manipulate and arrange the same thoughts and ideas in multiple ways, to see what works best. When students have completed this stage of pre-writing, they should be able to clearly articulate their thesis, as well as the main supporting arguments.
Ask students to construct an outline based on their pre-writing. At the middle school stage, a five-paragraph structure usually works best. An introduction explains the thesis, followed by three body paragraphs that support the thesis. The conclusion paragraph synthesizes the information and reinforces the thesis. Show students how to flesh out the main structural points of their argument created in the pre-writing stage with sub-arguments and examples.
Give students narrowly bounded writing assignments that focus the scope and purpose of their work. Structure assignments with a specific audience in mind. For instance, students could write columns for a fictitious school newspaper, with each student writing a separate "section" of the paper.
Require students to revise their own writing before submitting it for grading. Ask each student to submit a "rough" copy, on which they have marked changes and revisions, along with their final work.
Emphasize publishing as the final step in the writing process. Remember that "publication" in this sense simply means connecting the piece of writing with its intended readership. Although not all students will be published, by encouraging publication you encourage students to think of writing as a purpose driven activity, rather than an academic exercise. Develop and maintain a list of publications which accept student work, and encourage to submit their work. Most schools receive notifications by mail of writing contests for which students are eligible. Post these notices conspicuously, and be sure to announce them to the class.