While essay writing is a large part of high school and college English, it's important before you start assigning page counts and subject requirements that you explain to your students just what the purpose of writing an essay is and how the students can fulfill that. An essay can be written to inform, persuade or entertain, and sometimes those purposes can be mixed. Show students that your essay has to take a certain view; otherwise your essay might become meandering and confusing. Point out that you can persuade while being informative if you make your arguments clearly, or that you can be entertaining while you persuade by writing in a fun or comical manner.