One of the best books I've ever read, «The Inner Game Of Tennis», by Timothy Gallwey. His master piece was transformed in coaching inspiration for many authors, as sir John Whitmore.
As I finished this book, I realize I can't never forget the existence of a Self 1 and Self 2 that are working hard in my decision system. But what is this?
«(...) The "I" and the "myself" are separate entities or there would be no conversation. (...) One, the "I", seems to give instructions; the other, "myself" seems to perform the action. Then "I" returns with an evaluation of the action. For clarity we call the "teller" Self 1 and the"doer" Self 2.»
So, when we talk to ourselves, critisizing what we've done, what we do is puting Self 1 telling something negative to Self 2. As Timothy has written, the key to better anything lies in improving the relationship between the conscious teller, Self 1, and the unconscious, automatic doer, Self 2.
Anyway, I suggest you to read this masterpiece, it's a small book, around one hundred pages, that will give you hints how to perform better, how to control your emotions, how to deal with your two realities.
Self 2 is a wonderful machine, perfect; Self 1 is our ego, centered in status quo and very critical. The solution of a good performance is a well relationship between the two selves.
It's what Timothy calls of «letting go, slowing the mind, relax, accept the reality and go forward without criticizing».