I primarily carry IWB. I've experimented with other positions, but IWB just works best for me overall. I carry under an untucked shirt, and have practiced that way. When I had access to a range with programmable turning targets I would practice reacting to the targets. My baseline drill is 2 good hits, at 2 yards, in 2.0 seconds or less, from concealment. With my 642 I could typically do this in 1.6-1.7 seconds. Not great, with room for improvement (1.0 second is the goal), but not too bad, either. I haven't timed myself with my current EDC (Beretta PX4 Compact 9mm), but my subjective impression is that it's not a great deal slower.
I've practiced with my jacket for cold weather. Fortunately, my jacket is cut such that I can use the same drawing method, albeit somewhat slower because of the extra bulk.
I've practiced doing weak-hand draws, but I'm considerably slower since I lack some flexibility in my shoulder (working on that, though).
I've practiced from awkward positions, such as laying on the ground on my side, prone, and supine.
I will rarely pocket carry, and practice that, too. In fact, practicing is what led me to conclude that pocket carry is not an optimal method for me and is the major reason I rarely do so.
I carry my 642 in an ankle holster as a BUG. And yes, I've practiced with that, too, which has also led me to believe that this is not an optimal method as a
primary means of carrying a gun. However, the main reason I carry a BUG in an ankle holster is it gives me better access to a gun while sitting, especially when driving a car, than my primary IWB gun.
I also practice one-handed reloading and malfunction clearing, both weak-side and strong-side. Wanna have some fun? Do a weak-handed draw from an IWB holster and do a one-handed, weak-hand reload with a snubby revolver.
Having said all that, I prioritize my practice time with drawing while moving making up the bulk of my practice. I practice the other techniques periodically to maintain familiarity, but they're generally not part of my regular practice routine.