I think a good lesson about social media etiquette and netiquette would be to start off with what one could say about or to another student online and positive ways in which one can convey their ideas and thoughts.
This is an example of how teachers use paper blogging to teach students quality commenting skills. You can read more about paper blogging here - http://tvstechtips.edublogs.org/2013/09/09/when-paper-blogging-trumps-the-computer/
Student blogs, digital portfolios, blogfolios. Whatever you call them, this comprehensive resource gives you lots of ideas about how teachers are helping their students to create their own online space.
Our March 2013 Student Blogging Flipboard Magazine. Contains all the weekly challenge posts and the work done by student and class blog participates. Great way to see what participants did during the challenge.
Creating images from text is a good way of enhancing posts with images. Read Larry Ferlazzo's post on the tools he uses to make images from text to form quotes that he pins into Pinterest and uses for posts.
This blog is a 10 week course for students learning to blog. They may have done some work with other teachers, but this is all about setting up their own blog, step by step.