How can i prepare myself for duke?

starting this school year i will be a sophomore and i love duke more than anything. but i had a bump transition into high school with other problems and i got a c and a few b's and now i'm 61 in my class of 200 ish. how can i bring myself up to duke standards? i will honestly do anything. I'm already an avid part of the community and i'm in band (all state bassoon) and color guard and varsity swimming plus fta, and pep club, so i have extras curricular down. if you have any tips about anything i'll gladly take them :)