Do you want to sell more?

If so call 5 of your company's existing customers and talk to them.  Find out why they bought from you and why they're loyal to you.  This will give you insight into the mind of your customers and will better help you position your services to your prospects. 

Do you stand while talking on the phone?  If not try it and see if your calls go better.

Provide answers to the problems and questions that your customers have.