Authorship involves three interacting elements: agency, substance, and expression. Each is critical, and they all feed each other. Composition activites that do not attend to all of these elements are much less likely to result in high quality written or multimedia products. When I discuss authorship, I am referring to any sort of composition in any medium, including written or multimedia compositions across genres. While the technical aspects of composition vary across media and genres, the composition process is similar.
Attending to expression means effectively expressing what you mean to your audience in order to achieve your purpose. Expression is typically the most emphasized element in classrooms, yet it is difficult to engage students fully in the work of revising and editing without proper attention to agency and substance.
Saying something effectively
Attending to substance means clarifying your thoughts, shaping your ideas, and determining what you mean. Too often, when "the writing process" is taught and employed in classrooms, the early stages are rushed, such that students do not adequately develop the content of their compositions. The disproportionate emphasis on form often marginalizes attention to substance, which results in missing the ultimate point of communication.
Having something meaningful to say
Attending to agency means owning the communication task and having a sense of audience and purpose. Many classroom writing activites overlook this important element, and thus both the substance of the writing and the expression of the writer's thoughts suffer. If writing is merely an exercise, without the exigency of genuine communication, then the quality of the product is likely to suffer.
Wanting to say something