There's an element of practice too. Ideally, you want a very thin layer of oil to cover the base, or maybe even less. It doesn't need to be a lot. Also an average saucepan would produce quite a lot popcorn

To prevent burning, shaking and occasionally lifting off the hob is required. Also not adding too much corn helps a lot. The maximum a saucepan can take is when the entire base is covered with them.