Expect problems and eat them for breakfast.
Be gentle to all and stern with yourself.
Begin to be now what you will be hereafter.
Be kind whenever possible. It is always possible.
Either you run the day or the day runs you.
To be a good loser is to learn how to win.
Be thine own palace, or the world's thy jail.
Always desire to learn something useful.
If you're going through hell, keep going.
You never know what motivates you.
I'm someone who's done the opposite of whatever the received wisdom is, to keep your career going into your 50s.