Toya Lillard is not a real estate agent, but she has certainly mastered the art of giving a tour. As the executive director of 651 Arts, a Brooklyn-based organization dedicated to African diasporic performance, she has been proudly showcasing the organization’s new headquarters. Located across the street from the Brooklyn Academy of Music and the Mark Morris Dance Center, the fourth-floor space at 10 Lafayette in the city-owned arts complex is a major milestone for 651 Arts, complete with a black box theater and three rehearsal studios.