Forbes has an article on mentally strong people. Here are the headings of what mentally strong people avoid:

1. Waste Time Feeling Sorry for Themselves.
2. Give Away Their Power.
3. Shy Away from Change.
4. Waste Energy on Things They Can’t Control.
5. Worry About Pleasing Others.
6. Fear Taking Calculated Risks.
7. Dwell on the Past.
8. Make the Same Mistakes Over and Over.
9. Resent Other People’s Success.
10. Give Up After Failure.
11. Fear Alone Time.
12. Feel the World Owes Them Anything.
13. Expect Immediate Results.