Found this article on Forbes which I felt was super useful.
These are the 13 things 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
Be mentally strong!!!