This rise in the use of social networks presents new ethical, legal, and professional challenges for educators. Pre-service teachers need professional development to be cognizant of the content they are posting to personal social networks. The purpose of this mixed-methods study was to develop professional development guidelines to help pre-service teachers avoid common errors and misconceptions when using online social networks. A survey was completed by 121 pre-service teachers, which required them to decide what is appropriate to post to their own social networks. The findings show that pre-service teachers were unsure what images and text were appropriate to post. Based on the findings, the researchers provide eight professional development guidelines.