How to control my brain?

How to control my brain? I noticed when i talk with myself i didn't stutter that much but when I talk with others i stutter a lot. I know its all about in the brain, if you able to control your nerves you'll speak a lot easier. But when i have to talk to someone i suddenly get nervous, my confidence just drops down. There are some situations where i somehow managed to talk calmly like talking to a child or talking to high authority persons(principal, officer etc). While most of the time i struggle to talk even with shopkeeper. So how can i fool my brain to not panic on these situations!!!