The skin is not crispy because the duck is not blown after marinating. Generally speaking, we should hang up the duck after marinating, and blow dry the surface in a ventilated place (to have the wind blowing obviously). Then put them into a frying pan with a high temperature of oil. When it is cooked, it should be fried again. If you can bake in the oven at 150 degrees for another ten to twenty minutes, the skin is definitely crispy.