Also keep in mind that flavored oils and salt/spice combos are nice for homemade popcorn. I love to use macadamia nut oil for a sweet popcorn. For something really different: add 1/2 T of chili oil to your oil and after popping add a sprinkle of Chinese five spice with your salt.

i meant to say that i anchor the lid down to the pot using the mitts or towels, which generally involves gripping the pot at the handles.

sam1148's directions are great, but i make popcorn in an 8-quart pot all the time. i keep the lid on and shake the pot by holding the handles on each side with oven mitts or folded dish towels.

i also would add that i start the fire/heat off at medium-high, and once the popping starts coming on strong, i lower it to medium-low. i also will tip the lid back just a bit (so that the open "mouth" is facing away from me) for just a couple of seconds a few times during cooking to let some of the steam out, and i pour the popcorn out of the pot (tipping the pot away from me) as soon as it's done.

You really need a pot with a handle, you need to shake the pot as it begins to pop.
I find the ratio of enough popcorn to cover the bottom of the pot in a single layer, with enough oil to come up about half way of the kernels works well. When you hear the first pop start shaking. (this moves the popped corn 'up' so it doesn't burn on the bottom).

When the popping start to slow--to about 3 pops every 5 seconds. Remove from the heat. Take the lid off so you don't steam it and it'll crisp up.