The only thing I can tell you about the chin is it's a tough nut to crack for a rookie. Depending on your facial geography the technique can require very different approaches. The concept I found difficult is that as you hit different spots you need to be able to alter the angle of the razor very quickly and make overall very rapid adjustments. As I recall after months of struggling with it one day it just seemed to all came together. It was like trying to get a complicated math problem right. At first you just don't see the solution and then all of a sudden there it is and you wonder why you never saw it in the first place.