How do I rekindle my relationship with my friend?

Two years ago My Friend left my highschool, to go to a new school. Right before she left we got into a fight, it was completely my fault. I recently saw her and seemed to not be mad at me or anything and she hugged me...I guess were still friends. But before we were really good friends, how do I get back to being really good friends with her? What should I say to her online to make her interested in me again?What should I talk to her about?Should I ask to Video chat with her? I dont have her number.