Give them a call, send a letter, send an e-mail or fax, or better yet set an appointment with them even if it is a quick drop by just to let them know it was a pleasure to meet them and that you enjoyed the conversation. Use this time to reconfirm what they do and sell as well as restating your CDA business and the benefits that people receive from buying your products or services. In the sales profession it is true that the real work begins after you close a deal, that work being to build and maintain a strong relationship with your new customer by way of follow-up contact. 

Effective networking is no different; it is easy to make new contacts, but the real work begins after you have made the contact. It is at this point where you must build the relationship so that it will generate mutually beneficial results for both parties and in order to do so you must follow up and stay in contact.