1. Understand your students' reasons for writing.
The greatest dissatisfaction with writing instruction crones when the teacher's goals do not match the student's, or when the teacher's goals do not match those of the school or institution in which the student works. It is important to understand both and to convey goals to student in ways that make sense to them. Are the students required to take other courses? If so, which ones? Will those courses require writing? If so, what kind of writing?
This is not to say that your courses should only be in service to other courses. However, if your curriculum includes a lot of personal writing, and the students' other courses do not, what is your think it has? How do the skills learned in kind of writing? What benefit do you think it has? How do the skills learned in personal writing apply to other types of writing? Answering these questions will help you to find a focus for the writing that is to be done in your class.