I've watched everyone else say goodbye to her and it seems pretty easy so far.
Some people say something funny so that she will laugh. This seems like a good tactic because it leaves a happy last impression. Some people act like it's no big deal and that seems to work as well because then no one is upset and there's no awkward sadness. Some people give her a hug or a high five. Most people say "have fun" or "write me", and I guess those are good things to say also.
Everyone seems to have a way but me.
I really don't know how to do this.