Boiled down to its thickest meat-sauce, psychological successive approximation is a wildly technical way of saying:
Set a goal.
Work toward it.
Review the successes and failures.
Celebrate your healthy responses and choices that approximately match your desired outcome.
Then set another goal a bit further out and do it again.
Do this daily. Do this with your art. Do this with your attitude. Do this with your relationships and faith and decisions. One step at a time, in one area of life at a time, and you'll see compound growth take shape.