Do you see Bruce Wayne goes around and tell people he is Batman?
Don’t talk loud, don’t talk big; unless you are delivering a speech; and you have substantial research evidence to back you up. Otherwise, it is wiser to be perceived as stupid by keeping your mouth shut, then to open your mouth and confirm it.
If you are really good, you don’t have to do much to prove it, people will find out and pass the word around.
Do not despair if people fail to see the good in you; it probably means you still have much to learn, or you have been doing good to the wrong people.