The principal runs the show and sets the tone and culture for the entire school. She solves problems, creates rules, polices the students, manages the staff, acts as a mentor, evaluates classrooms and, most importantly, constantly communicates with everyone from the teachers to the parents to the school board. It's a complex job and one that can't be done without parent support.
Most principals were teachers at one point too, so they're quite familiar with classroom dynamics, working with children and the importance of parental involvement. They'll often make an effort to engage and help parents feel welcome, but don't hesitate to be the one who reaches out.
Find out if the principal is holding any meetings, orientations, events or open houses to get to know parents, or consider working with other parents to host your own "meet the principal" breakfast or coffee hour.