I use this method with a flat bottom pot (peanut oil and salt only), and I find that if I don't shake it from time to time, it will sometimes burn a bit before all kernels have popped. So, about halfway done, I shake and/or vertically bump the pot to let kernels settle back to the bottom.
As the popping slows, I take the lid off entirely (there's enough popcorn at that point to keep new popping from splatter or jumping out), and add salt, and then rotate the bulk of the popped corn with a bump to one side, salt again, bump-rotate, etc, getting the salt on it evenly without letting it cool too much. I like popcorn that's just-popped hot.
Two other notes:
I only use peanut oil, because at fast popping temperatures, some oils smoke. The popcorn does not taste like peanuts, if you'd worry about that.
I use more oil than most commenters, such that the single layer of kernels (3/4 cup in my pot) are nearly submerged at the start. Cleanup is more involved than a wipe of the pot, but the popcorn is a lot tastier and I don't need any butter or parm.
