Try this before your next meeting. Sit quietly for a few minutes (even if it's in the parking lot in front of the customer's business). Think about your favorite beach or other "happy place." Now, imagine how you want to feel when you return to your car after your meeting. As the meeting progresses, your subconscious mind will help you behave in such a way that you'll get those feelings. Great performers in all fields use visualization to improve performance. Feeling the feelings you want in advance intensifies the result.