I'm assuming this is OG/Noir we're talking about...
If you're not getting much smoke and it's harsh, you are underpacking the bowl and/or don't have enough holes poked in the foil.
If you are getting good smoke and it's harsh, you have too much heat on there. Keep in mind there is a difference between harsh smoke and throat tickle, the latter being more of an after effect. Throat tickle will go away once the bowl is properly warmed/heated.
Here's a more recent video that John made with Eric.
There is also a part 2 and 3.
The easiest way I can describe it is to pack it in tight and full until it is about level with or slightly higher than the top of the center hole of a Tangiers phunnel. By tight I mean the tobacco doesn't compress anymore without sponging back up. It's about right when you're squeezing juices out when you try to pack it tighter. The foil test in the above video accomplishes the same thing so it's not really necessary once you get a feel for packing it right.