1) Ask for feedback. Your assistants observe you regularly. Get their input on how well players are getting your messages. You can evaluate their communication as well. Everyone will improve when you ask for specific input. For example, your coaches can critique one another in a coaches only meeting on how a morning meeting with players went.
2) Tape your voice at team meetings. This is a good way to check your pronunciation, speed of delivery, tone, loudness and other vocal variations. Experiment with your voice to achieve new effects. Be prepared for a certain amount of dissatisfaction the first few times you hear yourself on tape. Most people don't like the sound of their own voice.
3) Record yourself on videotape. Many teams now video record practice. This is a great way to critique yourself visually. You’ll pick up on mannerisms and speech patterns (both good and bad) you never knew you had. Seeing yourself communicate in the practice setting is a great way to build on communication strengths and pare down weakness.
4) Review your communication. After both recording and video taping your voice, you will hear how you sound to other people. This will give you the opportunity to weed out undesirable words and sounds and body language.