The expression on your face is a reflection of your thoughts. You can change your facial expression by changing your thoughts. Years ago, I noticed 'older people' in general often looked angry. It seemed to me that their faces went into a default expression when the person did not have a reason to be smiling about something, and that default expression was not pleasant. By accident, I have found more things to smile about.
Humans tend to hang out with others like themselves.
YOU ARE , and you are who you think you are. If you are peaceful, personally powerful and successful, you will make that presentation. If you are moving towards that goal, you can support yourself by making the presentation that states your ideal personality. When you change the outer, you are supporting change in the inner - which is your thinking. It is the person you intend to become.