If you are not trainng the mind.....

The Russians have a term “psikologicheskaia zakalka” which translates to tempering of the will or psychological hardening. How do you train your mindset as a warrior? If you are a trainer of warriors, how do you incorporate this into you training in order to build well-rounded (physical, mental, and spiritual) warriors? Are there certain techniques or drills you use that seem to work?