Every one of those roles must be filled by one who discovered the party, had a positive first impression, and joined with a motivation to become active and make a libertarian difference. Most often, the critical experience is when a person attends a meeting of a local LP group. Learn from other successful groups like Toastmasters and service organizations. For instance, at each Toastmasters meeting, one member is the designated Greeter. The Greeter spots every new person as they arrive and introduces him or her to all the members.
Members wear name tags, with the organization name and any offices held.
The new person is also given a name tag. Nothing sounds better than one's own name. Make it easier for current members to address the newcomer by name, and vice versa. You are the messenger for the libertarian message. People respond to how you look and present yourself before they get to the content of the message.