I must not fear.
Fear is the mind-killer.
Fear is the little-death that brings total obliteration.
I will face my fear.
I will permit it to pass over me and through me.
And when it has gone past I will turn the inner eye to see its path.
Where the fear has gone there will be nothing. Only I will remain.

The Bene-Gesserit “Litany Against Fear”… I say this when I am dealing with great pain.  I know this sounds stupid, but when I recite this in my head, usually by the third or forth repetition I am back in control and can continue with what I am trying to do… such as standing up on a broken ankle, or other severe mind-numbing pain.    I said this when I shattered an ankle.  I said this when I took a round to my vest…

I also said this before I shot a 298 at the MAG-40 class.  It’s not necessarily about fear… but more about focus.  I can’t explain it, but it works for me.  It might work for you too.