My son recently started working with a phenomenal pitching coach who spends a lot of time talking and working with my son on the mental side of the game. It all revolves around "focusing on the process, not the outcome." It has worked wonders for son's baseball performance. It has also been very helpful for Dad as well! 
Not only am I redirecting my focus (from outcome to process) but I am exposing all of my high school students and athletes to this philosophy as well.
As we all know, baseball is a game of failure and there are so many things outside of a players control. Are there some players who just need a good ole swift kick to the behind (figuratively speaking), definitely! However, how many times have we seen the player who works his tail off...first one to practice...last one to leave...go into a slump at the plate, in the field, or on the mound? It is going to happen to every one of them at some point during their baseball career. Helping players to understand that they are not always going to be able to control the outcome but can always control the process, is a great philosphy to introduce as soon as they are old enough to understand and implement.
Here is a great article that does a much better job of explaining this philosophy. I cannot stress enough how important this can be for young baseball players, if implemented correctly.