That and other recommendations are part of an eight-page social media guide for students 13 and up recently rolled out by the city's Department of Education.
The "Student Social Media Guidelines" aim to teach teens how to be responsible on the Internet.
"Part of being a successful citizen is understanding that social media and digital communication are essential parts of our world today," the guide begins. "It is important to recognize that access to information can result in tremendous advantages, but it can also create new responsibilities of which students should be aware."
The city advises teens to use social media and the net to establish a positive image and to take responsibility for content they've posted. Cyber bullying, the guide cautions, should be taken seriously.
"At our school, students know that if there is ever any drama that carries over to the online world, our teachers and principal have our back," Kevin Torres, a student at Hudson High School, said in the guide.
The city also tells students to consider consequences of social media in the classroom and future workplace.
"Because online posts can never be completely deleted, it is important to make sure that each post is something you want to live with," the guidelines read.