I will get each and every member to imagine taking the penalty with out the physical ball. Get them to imagine taking the kick and scoring. This can be done on the field itself or off site.
Next, get them to imagine kicking it past the keeper. Again just imagination.
After that, I’ll add in the imaginary disctractions. Imagine kicking it to goal.
then, I will add in physical distraction, using actual sound. Maybe recorded or simply sounds of crowd, a car or bird flying by.
Lastly, I’ll get them with their mentally imagined kick, get them to kick for real.
Not sure if this is the best way but worth a go I suppose.