Most professional school programs seek students who are involved in their campuses and communities. They also see healthcare fields as service fields, so a track record of service to others is an important part of your application. Ideally that track record is well established during your college years rather than just starting the year of your application to their program. If you aren't sure what kind of volunteer work you would like to do, you could start by looking at student organizations. Many student organizations are service-oriented and provide a good way to get involved (Habitat for Humanity and Big Brothers/Big Sisters, for example). Purdue has hundreds of student organizations in which you can participate. To find an organization that interests you, go to www.purdue.edu/getinvolved.