So obviously I don’t know you at all, and this might not be applicable or possible for you, but as some one who for a long time just didn’t “get it” and now feels like they do, some tips:

When you interact with someone, smile and ask how they are doing.

Even if you don’t continue the conversation beyond “how are you? Good, and you? Good”, you interacted with the world, and had a non-negative result.

Being able to generate positive interactions is the first step to feeling comfortable in the world.

Be brief. Listen more than you talk, but when you do talk, say useful or applicable things. Ask relevant questions to learn more and keep the conversation going.

When someone is talking, try to think of a relevant question based on what they are saying. They talk about a trip, “was that your first time there?” Talk about a hobby “what got you interested in that”, talk about their work, “whats it like dealing with ___?”

The more you talk, the greater the chance someone isn’t interested in what you say. The more they talk, the more you learn what interest them, making conversation easier.

Small talk with someone is just talking about things you have in common. That’s why the weather is such a cliche but useful one, because it’s the one thing you know both you and that person are experiencing right now. Talk about things you have in common with whoever you are talking to, and it will increase the likelihood you have a positive interaction. And having positive interactions is basically all there is to “human-ing”