Instead of telling students to use active voice in their writing, reveal their personal stake in active/passive distinction by showing them how people use passive voice as a way of manipulating them.
You will have no difficulty finding examples of manipulative passive voice in news stories. Look for stories about celebrities and politicians caught in embarrassing situations. Chances are they will pull out an apologetic non-apology: “Mistakes were made” or “I regret that my family was hurt.”
This approach gives students a reason for paying attention to a grammar point they typically shrug off as irrelevant to them.