Application help !!! 10 points for best answer!?

I applied for 7 different jobs and out of the 7 only ONE called me.. i cannot figure out why, maybe because i am 16? but ill be 17 in january.. i applied for Kohl's, jcpenney, bath and body works, bonton, Maurice's, and a few others.. what could i improve on to get companies to call me in for an interview?!