Think about the standards you want to uphold as a team. What will promote a productive, positive professional environment? What will promote a hostile work environment? The standards you adopt can make the difference between Google and Apple, for example.

Sample:

Members of the team are expected to be good citizens and to engage in responsible behaviors that reflect well upon themselves, their team, and their cohort of peers; to be civil to one another and to others in their campus community; and to contribute positively to the team project, common classes, and overall student and university life.