Awareness about the nature of your thought patterns is a critical component of general well-being and happiness. Fear is a particularly destructive quality of thought that can get in the way of living a full and fresh life.
One technique I use in conditioning my thought patterns is to monitor for what I call "fear-based thought". For any given thought, ask yourself where this thought came from. If it came from fear (fear of failure, fear of rejection, fear of discomfort, fear of any kind), take note that this is where this thought came from, and dismiss it. Fear-based thought instantly loses credibility and influence in your decision-making when you have identified it as such.
By doing this, it becomes easier to operate with lightness and fearlessness. Self-doubt can be replaced by self-support and adventurousness. You no longer operate from a place of loss-aversion. You're now playing to win, rather than playing not to lose.