A problem i use to have is that when i bat in the nets am a superstar when it comes to a match i had a severe nervous breakdown and let the pressure get to me, the key is have you thought about what you will do if don't make the team? you have havent you thats the problem dont worry about anything at all its not end of the world if you don't make it there will be more oppourtunities down the line, so the key is don't pressure yourself, practice leading up to the trial and just take away any worries or doubts you have live the moment enjoy your journey, don't think about what your going to do in there just do it and be natural.