Transition From Middle School to High School?

Hi all, I was just asked to give a talk to a big of parents of 8th graders (in the Spring, right before the 8th graders graduate). They asked me to focus on the transition from Middle School to High School. I have a ton of ideas, but I figured I'd reach out to this community to see if you might have any words of wisdom for the parents of incoming freshman? Perhaps about scholastic or social issues (or any other kind of issue you think is relevant.) What are some things you wish you had known before your kids were in high school? Thanks in advance for anything you're willing to share.