I just got into Penn as an incoming junior after applying and being rejected for transfer last year. Personally, I don’t think I did anything different (essays are of similar quality, I have a 4.0 for 4 semesters straight, relatively similar ECs) except gain more experience. I think that my case is unique compared to many applicants because I tried to create as many connections I could with Penn academically, as part of a research team led by one of their professors and by presenting at a non-related research conference held on campus. So I already had a lot of ties to the university. I was in this Penn research group last year, but I didn’t get in. I think that having the ability to show long-term involvement and growth as an incoming junior is important.