How could I improve my application?

Double emphasize this!

90% of West Point cadets were involved with high school varsity (not JV) athletics. Physical fitness is equal in importance to academics. So continue in varsity soccer, try to make varsity lacrosse, perhaps even expand to varsity track or cross country. Start practicing for the “Candidate Fitness Assessment.”
http://www.usma.edu/admissions/shared%20documents/cfa_instructions.pdf