Every Teacher Librarian needs a kit like this. Craig Badura demonstrates, in an ed tech blog post, how to use everyday household items to practically and visually guide students on aspects of digital citizenship of which they need to be aware. This kit could be expanded or altered to suit.
This blog post by Sarah B Weir refers to a list of 10 pieces of advice Professor Larry D. Rosen of the California State University gives to parents to help their children have a safe and productive online presence.
Stay safe online. Be a detective and check out the site. Can you trust the information? Compare it with other sources. Be a good citizen online as well. Make only kind thoughtful comments or else say nothing. Report anything you see that is inappropriate online.