Put your best ear forward. Listen well. One of the most important telephone etiquette techniques is to listen to the caller. Listen for both the content and the intent.
HELPFUL HINT:
Listen to the caller's opening statement. Their first words will usually explain the reason for their call.
Write down key points.
HELPFUL HINT:
Write down key points. Write down their name and reason for their call. It will help you to summarise it later.