As one other caller mentioned - what I do as a caller is avoid looking at that dancer AT ALL. That confuses me, and I will miscall if I get to caught up in what is happening there. What I do is look ASAP for the dancers who are doing the moves smoothly and well, and I call to them, making sure I call clearly at the start of the four beats before each move will start, and not at the two beats before that I might often use, to give a little extra time for the person to react. If there is a four in line down the hall, I will call for the turn also on beat five of the phrase before (just as above, just saying it differently) ensuring that they turn around and head back in time to cast off or do whatever needs to be done in time for the next move. If I call carefully and steadily and clearly at the appropriate time for a few times through the dance to the experienced dancers, I generally find that once I look at the problem area, it has resolved. Also - I don’t vary or shorten my calls, as I might otherwise, and I might say Neighbor balance and swing, or With the next couple star left - telling them who to do it with and what, or face across, right and left through - which way to face etc. especially on any figure that might be confusing.