I went to prestigious U.S. schools for undergrad and grad school, with ~3.8 GPAs. I have around the same number of scientific publications but they are policy-relevant topics, some have contributed to policy changes.
I got into the Env. Health DrPH track, I'd love to give advice but hard to know what was really important. I might be older than most of you here? My B.S. and M.P.H. degrees were obtained 14 and 12 years ago, respectively, and I have developed a unique interdisciplinary niche with publications in scientific journals and popular media since then.