Focus on the NOW

The mental side of the game has always fascinated me.  The number of posts that have been about or connected to that concept is surely indicative of that.  There are many areas within the field of sports psychology but I do believe there is one central message that is at the core in all that it teaches and hopes to improve in athletes.  That message is the importance of staying in the moment.  All those negative thoughts that creep into the minds of baseball players have their roots in either the past or the future.  A batter may have an unhealthy level of anxiety before an at-bat because of poor performance against a particular pitcher or may be worried about what might happen in the future should he not succeed.  Worries like letting teammates down, possible anger from the coach or parent, looking bad in front of fans, etc. cause powerful emotions that distract the player from what they need to do or think about in the present.  In essence, the player has a mindset that is similar to the following visual:
Too much of the mind is focused on the past and/or the future and not enough is centered in the "now."  The obvious problem with this is that the player who thinks this way is ultimately focusing on those things in which he has absolutely no control over.  The past is over and cannot be changed.  The future has not happened yet and therefore any fears associated with it may or may not occur.  The future is just in one's imagination and is not based in reality.  Anxiety increases, in part, because of this lack of control. 
The goal of any sports psychologist is to get the player to learn, practice, and apply various techniques to help the player stay more focused on the "now" and therefore change the thought process to look more like this ...

Doing so gets the player to not ignore the past or the future but rather to give those events and imaginations the proper brain space.  The past and future do have value.  Mistakes in the past certainly should be analyzed in order to learn from them.  Striving towards future dreams, goals, and aspirations obviously require a player to be forward thinking.  However, too many thoughts connected to the past and/or the future mean less focus on the only thing a player can actually effect - the present.If you are a player who just can't seem to get the most out of your potential once the competition begins, my guess is that you are having a problem keeping your thoughts in the present.  If that's the case, first understand that you are not alone.  All players struggle with this to varying degrees.  The important thing is to recognize that a problem may exist, advocate for yourself, and take action.I've listed a number of posts ("Mental Side") and links ("Sports Psych") on the left side of this site to get you started.  There are many others online as well.