There are a few different things that adcoms like to see:
That you have had some exposure to what physicians do and what other health care providers do in settings where people are receiving professional services for injuries, illnesses, or in the context of health promotion/disease prevention (such as vaccines and "check-ups" for babies). This experience might include shadowing, employment and/or volunteerism.
That you have had some experience dealing with people ... including people who are not like you due to their age, socioeconomic circumstances, culture, etc. This experience can come from employment or volunteerism. It can be clinical or non-clinical. Keep in mind that some people are patients during the moments when they are actively receiving treatment for a condition but they are always "people". You can learn a lot of people skills and a lot about the human condition by interacting with all kinds of people in their everyday lives whether you are working at a convenience store or a public library or a halfway house or a sandwich shop.
That you have had given of your time and talent to "repair the world", to be involved in community service to the needy. Most often this is going to start with volunteer service that is either clinical or non-clinical and might (in rare instances) expand to full-time service for which you are paid a stipend (e.g. City Year, Jesuit Service Corps, Peace Corps, etc).
That you have had experience training and leading members of a team toward a common goal.(MAYBE) This can be in the context of a work setting or a volunteer program or club or organization.
Bottom line: the adcom asks itself: how has this person learned about what is involved in the career of doctoring? what does this person know about human nature and how to deal with people outside of their family or their comfort zone? does this person have a heart for service?
