Every player and goalie should go into their tryouts with the mindset that they are the best, but they are better than no one.
Be humble externally, but internally cocky. Be confident in your own ability, believe in yourself, but never be outwardly arrogant or conceded. Go in knowing that you may in fact be the best goaltender at the tryout, but you may still get cut, for reasons you cannot control.
Ultimately it is the coaches’ decision about who makes it and who does not. Your opinion of the other players is absolutely irrelevant. Once you accept this fact, you will be able to more easily move past the decisions of others and quickly prepare for the next challenge. This applies to both parents and goalies (and players). Accept the decisions you cannot change, learn from the experience and move on.
Use each tryout as a learning experience. DO NOT take being cut from a team personally. It is almost certainly not a decision based on you as a person. Simply take in the experience, learn from it and move on, being the best you can be each time you step on the ice and continue this process as often as it takes to achieve your goals.
So again, my advice is shoot for the moon, think big, dream big, aspire for the next level, enjoy the challenge, be diligent in your quest and don’t stop until you make it.