Get involved deeply in activities you enjoy. Not only will it help you form lasting friendships, but it is something that will look great on college applications. I got involved in theater construction and sound my junior year. Ended up doing it all through college. Met some great people, including my future best man. It will simply help you keep your sanity some days when things get overwhelming. Also, don't take things too seriously. A lot of people get caught up, believing that high school is going to be the prime of your life. This is far from the truth. Life keeps getting better and better as long as you keep pushing yourself. Don't get caught up in "now or never" scenarios.