Worrying about what other people think of me

I spend so much of my time worrying what other people think about me when I’m in public situations. If I could stop caring and just start being the real me, I feel like I could make so much more of a difference in the world. How do I stop caring? I’ve become very conscious of my thoughts over the last several months, but even with that awareness, nothing seems to be changing. For example, I go to church, I focus on smiling and acting the way I think I should act for everyone to like me, and I end up not focusing on other people or really paying attention to the conversations I’m having with them. I feel like if I could change this way of thinking, I could do so much more with my life. How do I start making change actually happen?