No matter how prepared you get before the call, you need to make sure to to get your head in the right place as well. You need to have your notes and your talking points ready to go. Know the content and the desired responses, and the reasons you are asking the questions, and know your follow up response once you've gotten your answer.
No reason for dead air after they give you your answer, you should be involved in the conversation, and ready to move on to the next topic if you are satisfied with the previous answer. Basically keep your head in the game. Avoid the distracting thoughts that might derail you. Put the content you're after first.