Referee The D

[tomegun]

Going along with what Mark Dexter said, it is also helpful to know the numbers of the players in your primary. Keeping this in mind helps you focus on your primary, ref the D and know who the foul is on. Some supervisors like to hear the offending players color and number right after the whistle. This helps in knowing who the foul is on and it also helps with your perception. If you do this then someone might think "he/she knew that foul was on blue 22 right away, he/she must be right." That can go a long way because we have very few friends while we are on the court.