Becoming more successful (2,3,2,3,2)
I believe the answer is:
on the up and up
(Other definitions for on the up and up that I've seen before include "Continually doing better" , "In a state of continuous progress" , "Continuously progressing (2,3,2,3,2)" , "Steadily improving (2,3,2,3,2)" , "Getting increasingly better (2,3,2,3,2)" .)