The Woes of a Slow Learner

I need remedial running lessons.  How on earth am I supposed to increase my cadence and not my speed?  I tried taking shorter strides so that my feet would hit the treadmill more often, but that just made me speed up and get more winded.  Even trying to land on the balls of my feet didn't work.  Clearly I'm doing this wrong.  It is frustrating to be so incompetent!!!