How can I become more confident?

I am a very shy person in my 20’s I hate new people and hate new things aswell as change. I have been to psychologists all my life but all they did was talk to me not act it out with me. I/m trying little things nw and again like posting a letter with my mum being only a few feet behind me. If you’re like me please give me hints on what you do and why you’re like this?