Work hard, be smart and safe. I saw many people in my high school class do stupid things that really made it difficult for later in life (got arrested for underage drinking, car crashes, got pregnant, ect.). Overall, make sure you have fun. You only go to high school once. Go to pep rallies, prom, participate in sports and extracurriculars, and cheer on your other classmates in theirs. Don't be afraid to try new things and to be yourself. At times high school can be hard, but after you get out you'll realize that it was a lot of fun.
Let's just say this...it's what you make of it..literally. If your gonna be stuck up and act like your better then everyone, your gonna be miserable. But if your nice and easy going you will have a blast! If you like to go out to parties and stuff, be prepared! There's gonna be lots! But whatever you do, DO YOUR WORK! And don't think that just cause its freshman year you have time! Cause that's when you wanna pay attention the most. I was always told "don't let 4 years of misery with homework and classes ruin your chances of being happy for the rest of your life" i wish I would have listened, now I'm kicking my self in the ass for it (excuse my language) just work hard and have fun! Highschool is actually very fun for the social part! (: