When the Rational Becomes Rational
Do not close your mind off to things. Don't say you'll "never" be able to do something, such as speaking in front of 100 people. Right now, it is rational to say "I can't do that yet". But it may not be rational to say "I can NEVER do that - I HATE public speaking!" MAYBE that will be true... but MAYBE your thoughts and beliefs may change in the next twelve months.
The therapy solution: (It's easy): Just keep your mind OPEN to things by saying "MAYBE or PERHAPS later on I will be able to do that". Don't close your mind off by saying "never" "can't" or "hate". Your thoughts should be kept conditional instead.
Life will change for you if you keep your brain open like I've just explained. Step by step, little by little, things will add up.