Every time you interact with someone in your database, whether it be by email, phone, face to face, or some other method, you should be recording that contact in your NationBuilder control panel. This will help you keep track of who you have reached out to, give you more insight as to what kind of a supporter they are, and make sure that the outreach efforts of other people in your organization don't overlap with yours.

In order to log a contact, go to the individual's personal profile page in the control panel (you can usually do this by clicking on their name anywhere you see it in the control panel), and click on the Contacted tab. There are radio buttons you can select for the type, method, and status of the call. You can also post a private note about the contact, choose who contacted the person under Contacter, and designate a support level.  

You can edit the radio button options under type, method, and status by going to Settings> Contacts. 

From your control panel dashboard, if you go to the Contact View tab you can view statistics for contacts by people with control panel access. See how many contacts someone made that day, that week, month, or all time.