I just submitted my ED app, so this is all of the final info that I included in my application. Any insight is greatly appreciated 
General info: white female, I attend a private school in NY (60 kids per grade), very academically competitive school
GPA: 3.9 UW, my school doesn’t give a cum GPA, but I got a 3.9 freshman and sophomore year and a 4.0 junior year. I’m too lazy to calculate the cum so I’m just gonna say 3.9 ish. No rank available either.
Test Scores:
ACT: 35 (E: 36, M:35, R:35, S:32)
Math II: 800
Bio: 750
APs (self-studied for all since my school offers no AP courses): AP Bio (4), AP English Language (4), US History (4)
ECs:
Yale Young Global Scholars Program Participant (2019) - Creative Arts and Media Program
“Baroque Art,” University of Vermont (Summer 2018, 4 weeks) - got college credit and an A in the course
Founder of an indie Nail Polish Company (6-12) (donate all profits to ASPCA - ASPCA Brand Ambassador Award)
Intensive Italian Language (9-12) (outside of school)
Member, Red Door Club (9-12) (Give school tours to prospective families, hold panels and open houses, promote school’s mission)
Intern at Robert Simon Fine Art (art dealer) (Summer 2019, Intern, 3 Weeks)
Team Captain, Varsity Tennis (9-12) (Number 1 singles player. As captain, I led the team to the finals of the league tournament and was voted league all-star for past three years)
“Art History,” Sotheby’s Institute of Art, New York (Summer 2018, 2 Weeks)
Member, Upper School Dance Company and Choreography Club (9-12)
Art History Club (9-12, President)
“Writing the Expository Essay,” Brown University (Summer 2017, 2 Weeks)
“History of European Art,” Oberlin College/Great Courses Online (Summer 2017, 2 Weeks)
Awards:
Published in Concord Review (11)
Published in The Schola (11)
First Prize - International Philosophy Writing Competition (13,000 entries and only one first prize winner) (10)
Silver Medal - Le Grand Concours - National French Competition (10)
AP Scholar (10-11)
Essays:
Common app: I would give it an 8.5/10, my counselors loved it, but I would not say it was necessarily the best of the best lol.
Why Dartmouth: It was only 100 words, so very tricky to write. Talked about the art history program in depth, D-plan, study abroad (specifically the FIRE (study in Florence) program) and aspects of the community I fell in love with when I visited. I might give it an 8/10.
Extra Supplemental: Talked about how my inability to paint on large canvases led to my obsession with doing nail art/painting my nails. I also tied it to how I started my mini-business with nail polish in middle school. This is my favorite essay by far and it was very well-received by my college counselors and others who read it. I might say 9-9.5/10, but who knows.
Thank you in advance to anyone who responds!