In this paper in One Trusted Adult, consultants Brooklyn Raney and Ryan Donaher suggest guidelines for working online with middle- and high-school students in ways that build trust and maintain boundaries. Some excerpts, directly quoted as noted:

• Clarify intent. “I care about your health, happiness, safety, and success, and our inability to meet in person doesn’t change that. I believe a routine and a sense of normalcy will help us during this unprecedented time.”
• Set up for success. This includes having a daily routine with students, dressing like you’re going to school, sitting at a table, and asking students how you can help them.
• Build a safe virtual space. “Do not assume your students will automatically bring classroom norms with them into this venue. Take time to reiterate all of the rules that still apply, and any additional ones that need to be set up in order to protect the safe space needed to learn. Ask for their contributions and feedback to the list.”
• Be fully present. “What students will notice more than anything is whether or not you are really with them.” That means not being visibly distracted by phones and other events.
• Model vulnerability. “There is no need to pretend you know what you are doing. Ask for their patience and understanding, request their help, and model learning something new at a rapid pace and delivering it before it is fully tested.”
• Create opportunities to contribute. “Seek opportunities for them to lead, teach, inspire, and support each other virtually.”
• Provide structure and predictability. “Beyond your curriculum and content, consider the fringe moments, the intentional and unintentional connectors that happen in your classroom, that can be creatively translated to your online space.”
• Reassure and encourage. “Try to say every name of each of your students every day. Let them hear their name in a positive way, whether as a greeting or being called upon to share. Allow your students an opportunity to be seen, heard, valued, reassured, and encouraged. And never, ever underestimate your role as a trusted adult, even virtually, in the lives of these young people.”
• Work with two shoulder partners. “Continue interacting with young people as if their parents are on one of your shoulders, and your direct supervisor is on the other. Then, assume all your virtual interactions are being recorded – would you want this recording to go viral? For your safety and security as an educator, and for the safety of your students, continue building trust with young people through the establishment of boundaries, and create educational moments you would be proud to share.”

“Tips for Maintaining Trust and Boundaries with Virtual Students” by Brooklyn Raney and Ryan Donaher in One Trusted Adult, March 2020; Donaher can be reached at ryan.donaher@gmail.com.