Either you run the day or the day runs you.
Go for it now. The future is promised to no one.
Be kind whenever possible. It is always possible.
Always desire to learn something useful.
If you think you can do it, you can.
Know or listen to those who know.
Expect problems and eat them for breakfast.
By failing to prepare, you are preparing to fail.
Never complain and never explain.
Be gentle to all and stern with yourself.
There are simply more young people than there ever were. You get this feeling of strength. Also, large numbers can be a drawback, making it difficult to lose one's anonymity.
Teenagers today are more free to be themselves and to accept themselves.