Teach students, that just like person-to-person interactions, online interactions should be respectful and follow some etiquette rules. Also, just like in the classroom, students need to know how to appropriately and academically respond to peers. This requires teaching students academic conversations that provide an opportunity to present ideas and respectfully disagree.
This resources provides task cards that show sentence frames for classroom discussions. These cards can be printed to use for verbal discussion. The same sentence frames can also be used to post comments about student work inside a google doc or classroom.
Flipgrid is a collaborative tool for students to use to record their thoughts, give explanations, and more. Teachers can set the permissions so that students can see each other's videos and comment on them.
Google Classroom is a great environment to teach students how to collaborate with one another effectively. Because of the nature of Google Classroom, it is easy for teachers to monitor the comments and collaboration happening on posts, as well as documents.