Your Are Your Actions
One of my favorite scenes in Game of Thrones was when Joffrey felt the need to declare himself king to the small council, only for his grandfather, Tywin, tell him, "Any man who must say, 'I am the king,' is no true king."
If you have to say who you are, what you are, what your value is, then you're not showing it enough in your actions, in how you carry yourself. And people are probably not giving you the treatment that your position or title demands.
If you're a leader, an entrepreneur, a teacher, a parent—act like it. Let your actions, accomplishments, and attitude speak for you.
It is through those that you gain respect, not in your verbal reminders.