I wish I knew exactly what it was that has made my application stand out but I suspect it is a combination of factors
1. Personal statement is very strong - this is the one thing that I know for a fact. When I went on interviews, almost all of my interviewers told me how much they enjoyed reading it. I worked very hard on mine, revising it over and over again. I wrote about stories that impacted my interest in medicine. If you think medical schools don't fine comb through applications looking for qualities/characteristics that are consistent with their mission, you are wrong. I have found that they absolutely do. I wouldn't have gotten any interviews based on numbers alone.
2. Not the extracurriculars themselves, but they way you talk about them. I don't think my ECs very strong/interesting. I had some clinical work for a few months, research for 1 year with no pubs, student teaching, various volunteering. I would call my ECs average at best. When I wrote about them in my AMCAS, I included something that I learned from the experience and how it changed me. For instance, I tutored a few students outside of class. By the end of the semester, they had decided to pursue medicine because I was there to answer questions about it/encourage an interest in science. You can have amazing experiences in any EC - it just depends what you put into it.
3. Update letters/letters of interest - I didn't even know about this the first time I applied. This time, I actually have relevant updates to send to schools. Since submitting my AMCAS, I started a new job and new volunteer work. As soon as I submitted my secondary, I sent a update/LOI-hybrid letter explaining my updates and then talking about why I think I am a good fit at that school. One school even told me I was granted an interview because of the LOI.
4. Picking the right schools to apply to - this is very very important. I spent a lot of time researching schools that practice holistic admissions, who have MCAT medians ~30-31. If you don't have access to the MSAR, I would recommend buying it. There, you can see the 10-90th percentile breakdown of previous classes. I made a very targeted list of about 15 schools. I was going to apply to more but I also applied to 5 DO schools and got burned out with the secondaries after all of those.
5. Excellent interviews - I knew that if I had the chance to get to an interview, I could nail it. So I scrapped for interviews with letters of interest. Once I got II, I practiced for interviews. There are some interview videos online that made me go from mediocre interviewer to outstanding. I practiced with my brother, who is trained in interviewing.
6. Be confident - this isn't necessarily a requirement but it certainly helped. As a re-applicant with mediocre scores, I was terrified. But I would try to put this out of my mind and remember that even if the other people on Interview Day have a 33 and 4.0, I was also invited and the school saw something in me that they liked. I wasn't ready to attend medical school the first time I applied - I see that now. I was still in college and wasn't mature enough yet I think. Now I have been working in healthcare for the past 6 months and I have grown up so much. I can clearly articulate my reasons for going to medical school and I want it even more. If anyone is considering a gap year, I say DO IT. I wish I hadn't applied when I wasn't ready and did this right off the bat. It's the best decision I've ever made.
Feel free to PM me if anyone has any questions. I remember getting my MCAT score and bawling, having the paralyzing fear of retaking it again, and not doing it. I can't believe I am now sitting on an MD acceptance to one of my top choices. Don't lose hope 27-29ers! You can do it!!!