Do not assume that students know how to write. Davis (2009, p. 306-308) suggests teaching students the fundamentals of writing:

• Provide guidance throughout the writing process
• Remind students that writing is a process that helps clarify ideas
• Share your own struggles in grappling with difficult topics
• Give students opportunities to talk about their work in progress
• Help students develop a writing schedule
• Explain thesis statements
• Encourage specificity
• Emphasise the value of revision
• Refer students to available resources

Source: Tools for Teaching, Davis, BG, 2009