Give a little of yourself. Everyone says that teenagers - I hate that word too - are the most self-centered of humans.
But my advice is to prove everyone wrong and help a little around the house, take out the trash, vacuum, clean the garage, give the neighbor a hand, hug Aunt Betty, visit Uncle Joe, every now and then. When you do something minimal to make someone else's life a little wet.
Join something, anything, a club, a sport, a committee, an activity that makes your heart beat faster than that of a child who begins to walk, Stay away from television and cell phones, computers and video games for a few hours.
Try something new that you might like, not just something that pleases your parents or family, or gets you into the right college. Cheer up at your age, it all feels like it's determinative, but it's not, or if it is, it will shrink once you focus on something else.
Open up and share your heart with someone else who understands you, your humor, your music, your dreams, do not go out with anyone who makes you miss the wonder of family and friends or yourself. Find a person who will make you smile, laugh, and float back home.
Be yourself, because you are good enough. Everything will change for the better, trust God first.