There are many ways to teach persuasive writing, and utilizing more than one approach can be good for your students. Not all students learn the same way, so demonstrating by example how to write persuasively might reach some of your students. Carefully explaining written assignments or setting up in-class debates and then letting your students learn by doing are methods for teaching persuasive writing that might reach different learners in your class. And reviewing your students' work and giving them plenty of feedback can also be an effective way to teach persuasive writing.
This was great! You’re right, there are sooooo many ways to be persuasive. One thing that I do (when it fits) is to take a subject or idea that I’m attempting to share and dramatize it. Exaggerate it. It helps to get a point across. For example, a friend of mine just wrote a great radio ad for a business that wanted to let everyone know of ALL their many services. Which is no easy feat if you’re trying to stay away from being boring. So, he wrote an ad for the business as if you were ordering their services at a drive-thru fast food joint. This particular concept also would fit into your “Comparison” tip.