MD What can I do to improve my application significantly?

I have posted two threads concerning my chances for medical school, but none of them were really in the sense of improving in which I want to do. My goal is to attend a medical school in the big cities, which are all practically top 20 medical schools. Therefore, I was hoping you guys could provide advice to help improve my application. My MCAT score will be hypothetical for the time being.

Resident Assistant (1 year)
President of a Cultural Club (2 years)
EMT (Volunteer through my school's organization) (2 years)
Founding a Fitness and Weightlifting Club for the upcoming school year
Tutor for Chemistry paid through the school (1 year)
Chemistry Lab Floater (Similar to TA) (1 year)
Volunteered as a Tutor for a local high school (1 year)
Volunteered at Opportunity House tutoring/taking care of kids at a Day Care (2 years)
I also have been doing research for the past year and will continue doing so in the summer and the upcoming school year (2 years)

I plan on having my RA and starting the club as my significant ECs. I will be shadowing my friend's mom who is a pediatrician and plan on doing more shadowing this summer. I am a rising junior at the moment. I hope to start volunteering at a hospice soon enough, but is there anything I can do to improve my application significantly, it definitely comes off as cookie cutter to me. If I get a first author publication will that be good enough? Should I really take the initiative to set up some tutor program in our city or something significant in that aspect? As for stats lets say I have a 3.8+ and a 35+ MCAT

Any help would be appreciated, please and thank you