Like many coalitions it is important to have the right people involved in terms of their ability to impact issues and their "stake" in seeing things improve. David Crislip has an excellent model for think about who to include in coalitions generally with some good thinking about who NOT to include. For this particular set of difficult issues it is helpful to have a number of students from diverse experience in terms of drinking. Too often the students selected for such a coalition are from student government and the greeks but are underrepresented by more typical students who likely drink in more typical ways. Having local community (non-campus) participation can also be helpful including stakeholders who make their living from students drinking as they have first hand and experienced insights.