Since you're still in college and have never had another career, you would still be considered a traditional applicant.
Median cGPA for those accepted is 3.65, so try to raise your GPA.
Hopefully you already have some ECs from the earlier college years. It would be nice if some were community-service oriented, leadership-y, or teaching. Artistic endeavors and sports are also listed.
For a med school application, typical extracurriculars would include 1.5 years of clinical exposure. Gaining experience at a rate of 3-4 hours/week is fine. If you have the time, a broader experience gained in more than one venue would be desirable. Your gain two things from this: 1) the ability to talk with sick people, make them comfortable, and become comfortable around them. 2) Become familiar with a clinical environment, whether hospital, clinic, or nursing home, including a knowledge of HIIPA regulations and the importance of good handwashing and other disease prevention techniques. During your clinical experience you will hopefully meet doctors. These are the folks you ask for a shadowing experience which is a formal observership and not hands-on. Typically, one shadows 2-3 types of specialties, for 8-40 hours each, depending on interest.
Altruistic service is also desirable. If you gain your clinical experience through volunteerism, you have this covered. If your clinical exposure is via another type of experience, you'd need something additional to show your service-minded mentality; consider Humane Society, Habitat for Humanity, crisis hotline, soup kitchen, homeless shelter. Longevity in an activity is desirable.
Additionally, you'll want to have a peer leadership experience. This could be teaching or mentoring (provided you are guiding, directing, inspiring and not just regurgitating information), officership in an organization (if you lead meetings, organize the accomplishment of tasks, provide direction), starting a business, military service, directing a show, leading a successful charitable fund drive, organize friends for a campus cleanup, food drive, campaign for campus change, among many others.
Research: Is desirable, but not required. If you have it, more schools will seriously consider your application. The minimum is 3 months over a summer, the average seems to be about a year. Some have 3+ years and several publications. Research includes any scholarly investigation that enhances human knowledge, so it need not be bench (basic science) or clinical in nature, or even in the sciences.
You can get clinical experience with sick people through the workplace, for class credit, data gathering for a clinical trial, or via volunteerism. It can be gained at a free, family-planning, or private clinic, hospice, hospital, VA, residential home, rehabilitation facility, nursing home, as a first responder, among others.
Clinical patient experience is not always gained in a clinical environment, eg EMT, battle field medic, home hospice care, physical therapy aide, special camp environments. In such a case, you also should acquire some experience in a clinical milieu where doctors work, like a hospital, surgicenter, clinic, nursing home.
The advantage of gaining clinical exposure through volunteerism, is that it also is looked on as community service, an unwritten requirement for your application. Having nonmedical community service, too, would be looked on very postively.
Aside from a competitive GPA and good ECs, you'll need a good MCAT score, strong Letters of Recommendation, a well-written Personal Statement, and good interview skills.
That's most of what you need to do (irony intended). Well, a research publication would be nice, but most don't have that.
