Score from the spot under pressure. Pick a target before you start, keep a consistent run-up and a stable plant foot, strike cleanly with enough pace, and commit to the corner without changing your decision.
Ball on the penalty spot, keeper on the line. The taker picks a corner, runs up consistently, and strikes low and firm just inside the post. Practise one repeatable routine before adding power or deception. Keep the keeper honest, and watch for a lean to aim the other way. Rotate takers and keepers.
Penalties are missed for one reason far more often than any other, and it is not technique. It is changing your mind. A player who picks a corner on the walk up, then sees the keeper move and reconsiders during the run, arrives at the ball with no clear instruction and hits something in between. That is where the tame shot down the middle and the ball into the stand both come from.
So the first thing to practise is the decision, not the strike. Pick the corner before you place the ball, and commit to it regardless of what the keeper does. The one exception is a keeper who leaves early and visibly, and even then the change has to be made before the run-up starts, never during it.
The second thing is that low and hard just inside the post is the percentage ball. Top corners are almost unsaveable, which is why players are drawn to them, but the margin between the top corner and the crossbar is a few inches and the punishment for missing is total. Along the ground inside the post is a shot a keeper has to travel a long way to reach, and the miss, if it comes, is still on target.
The third is repeatability. Five or six steps, slightly to the side, the same every time. A run-up that changes under pressure is the tell that gives keepers something to read, and it is the part that goes first when a player is nervous.
Save it to your private drills, then change the animation, adjust positions, swap equipment, or drop it into a session block. Or start from a blank pitch and build your own.