It is so glad to receive the customer's respose, but what to do in the following days. You can ask the customer what is the business going on in his/her part? Is there any big progress in his/her part? is there any good news?

Besides business, maybe you can talk something else, such as hobby, sports, music. try to make friend with the customer, and if the customer think you are honesty, trustful, he/she would glad to do business with youl.