I have been able to practice one particular shot by asking the puller to set the trap at one position. You might start just shooting straight away targets, for example, to gain confidence.
You might also pattern your gun to see if your Point of impact is the same as your point of aim. I always shoot patterns at a 3' x3' cardboard with a bulls eye in the middle from 16 yds. to check the gun. I personally prefer guns that put about 60% of the pattern above the point of aim.