Crispness is created when the potstickers come in contact with hot fat and the water evaporates from the surface of the food. So preheat the pan and preheat the fat. Add the potstickers in a single layer (without touching). Cook until golden. Add liquid and cover with lid. Steam until tender. Then remove the lid and continue to fry until the liquid is all evaporated and the dumplings are crisp again. For the crispiest potstickers, don't stack on top of each other, add sauce or cover before serving.