I'm somewhat of a fanatic on popcorn style... Take with a grain of salt.
> Take one large pot (the kind that holds like 10qts).
Ideally a dutch oven or similar heavy bottom that distributes heat well. This makes the process nearly foolproof on any heat source.
> Add a bit of oil, basically just enough to swirl and have everything covered in an oil sheen, not enough to have them submerged.
If you are looking for "movie theatre" popcorn the "secret" is using (extra virgin) coconut oil along with flavacol dissolved in the heated oil with the kernels popped in it. I use 2-3tbps of coconut oil and 2tsp of flavacol for 3/4 cup worth of kernels.
Flavacol should not be used as a topping imo, but as part of the popping substrate.
> Cover
This is tricky. Covering traps moisture released during popping, and moisture results in soggy (or at least not crisp!) popcorn. You do need some sort of cover though for obvious reasons.
I found a pot+metal strainer combo that fits perfectly together, where the strainer has about as many holes in it as you could get away with without creating oil splash mess. This lets as much steam as possible out immediately upon popping with as little kernel contact as possible. A more easy to come by lid is using a mesh oil cover meant for deep frying.
The commercial poppers accomplish this by having a very small popping pan, which kernels get "pushed out" of fairly quickly after they pop into a well vented holding tub.
> Toss 1/8 cup butter in the hot pot, melt the butter with residual heat.
Disagree on butter on popcorn, but it's a personal preference. I find butter makes popcorn soggy due to water content - and the flavacol+coconut oil is typically what most US theatre chains use vs. real butter, so it's what I "expect" the flavor to be. That said, I sometimes do melt up some butter to switch things up.
> Salt(I prefer a salt grinder)
I prefer pre-made popcorn salt in a wide metal popcorn salt shaker to really get a nice even spread.
> transfer back to the mixing bowl.
One trick: If you are making a lot of popcorn "to go" (e.g. for a party later) the best way I've found to keep it fresh is inside doubled-up paper grocery shopping bags. This helps soak up residual moisture, and the difference is noticeable after a few hours.