As suggested below, more oil. Then wait (as you did) for testers to pop. Hold off on the sugar until it all starts to pop, if you add it too soon you are cooling the oil down, resulting in uneven poping which is why you have so many unpopped kernels, it's also why the kernels are sticking to the sides and the stir stick. Also the sugar can caramelize. Hope that helps. Good luck.
