Talk more slowly. Really listen to the customer. It is important that the support tech keep control of the support session in order to keep it as brief as possible while at the same time giving good service. Have the customer describe as succinctly as possible the problem or question. Keep the customer on track.
Many customers call with multiple questions or problems.
Deal with one at a time. Give some responsiblity to the customer for working with you. Passive customers may need reassurance. Determine whether the problem is within our scope. Refer the customer to other sources of information such as web pages or on-line help.