Thought this list was useful and helpful regardless of age; it reminds me also of Kevin Kelly, who says advice should really be called reminders :)
1. Focus your energy
2. Guard your time
3. Train your mind
4. Train your body
5. Think for yourself
6. Curate your friends
7. Curate your environment
8. Keep your promises
9. Stay cheerful and constructive
10. Upgrade the world
In tweet form:
He also did an in-depth podcast on this (I’ve only listened to part of it):