Only shoot flintlock rifles/pistols since 1998. Last 2-3 years - I try to get to the range 1 a week during April - October. Before that very sporadic. Usually 15 rounds or so from various positions - sitting, standing, with a rest, with a shooting stick and off hand. Concentrate more so at 25 - 35 yds - for hunting purposes. Routinely in a 3" diameter circle from a rest at that range. Fewer shots at 50 yds. Usually in a 6" diameter from a rest at that range. None at 100 yds.
I think my Lancaster fits better than the T/C. Never had any basic marksmanship training. Positioned the rear sight further down the Lancaster's barrel when I built it and seems to on target when I put cheek to stock. Will try the cheek weld suggestion. Not sure what is meant by follow through though or what proper technique might be
So you understand the basics, stance, cheek weld, sighting, trigger release and follow through. I recommend revisiting those basics along with practice as ,others have mentioned. To rise above average shooting it takes regular practice, but if you aren't firm in technique then practice is a waste of your time.
Revisit the basics, keep those firmly in mind as you visualize the whole shooting sequence in your mind (over and over). Now pick up the rifle and do the same thing, actually pulling the trigger (dry firing). Once the gunlock snaps keep your stance and sight picture while holding the trigger to the rear a moment before releasing it (known as follow through). In actual shooting you would hold that trigger in place (rearward) until the shot is off and the ball on the way to the target. If you can "call your shot" (know where the ball will impact the target) before it arrives at the target then you are becoming a better marksman.
Do you know how to work up a load for a muzzleloader? With a muzzleloader you shoot for the tightest groups first, then move on to sighting the gun for zero. Once you know the load (powder charge, patch and ball combination) your gun performs best with you will see a great improvement shooting it. At that point too, knowing where your gun shoots, you can move out to longer ranges. For hunting you need to zero the gun at your expected range for taking game.
dave