#1. It ain't as serious as you and everyone around you thinks it is. Laugh, live, and enjoy. Life is a one way trip. You get no do-overs or re-runs.
#2. Academics are far more important than your love life, your social life, your life as an athlete, or your life in gaming or role playing. Later in life you will remember the academic lessons in high school more so than you will remember what you learned in college.
#3 If you are bullied, Have fun with it. I was slammed up against the wall when I was a freshman. I yelled as loud as I could, "I don't care what you do to me. I am not going to let you give me a blow job!" I was never bothered again. Boys will grow logarithmically between the age of 14 and 16. Girls are going to become young ladies. It all gets better.
#4. Don't treat your friendships lightly. The close friends that you have grown and suffered with in high school will last you longer than any others for the rest of your life. Don't forget your friends. Don't betray your friends.
#5. Take care of your health. Stay physically fit. Your body is your transportation to the future. Do not smoke cigarettes. Do not partake in excessive alcohol. Eat fruit and vegetables a lot.