One of these techniques is Neti-Neti meditation. Neti-Neti can translate into "not this, not this." As a thought or worry enters the brain, the meditator responds, Neti-Neti. There is a wonderful yoga teacher who explained this to my training, wagging his index figure back and forth, as though dismissing each uppity thought that would try to tell him that it was his identity or his focus. No, the finger wagged, not this.
The Net-Neti meditation can be particularly useful for those of us who tend towards striving or who work in fields in which seeking acceptance is a large part of the job.
One of the things I wish I had known as a new graduate student is that the handling of rejection is an important part of being an academic. When it's job market season, the academic job seeker sends out dozens of applications, most of which will result in "no." The same can be true of journal articles, grant applications, and conference proposals. At times, it can feel as though the rejection is quite personal and it is as though the self is being extinguished under a tidal wave of rejection.
Neti-Neti can help remind us that we are not this. We care about and invest in our work, but we are not identical to it. When the work comes back rejected (or accepted!) this does not change who we are at core.
While many mantras or affirmations are positive (I am ___), Neti-Neti opens up certain kinds of freedom through its negativity. What a relief to not be this, to not be that.