That used to be me too. I'd stare and analyze everyone and had no idea how to get in. But then I realised something. People didn't make sense. Nobody cares about any insightful thing you have to say. At least, not in the beginning, and not in groups. They just want to keep the flow going.

So just go in and say whatever is in your mind. Do not over think it. But of course that's difficult to get used to.

So first, instead of thinking of what to say, I learned how to react. Don't try to contribute to the conversation. Try to react. When someone says something that's supposed to be funny, learn to laugh with everyone else. When somebody says something surprising, learn to look as surprised as everyone else and make a surprised noise. Like, "Oh!" or something. If everyone is impressed, try reacting likewise and say, "That's Impressive!" as a reaction. Of course it's an obvious thing to say, but people like pointing out obvious things. It's not smart, but it's not exactly dumb when people aren't looking for insight, just a reaction. It doesn't have to be fully auditory, it could be facial, or just a small noise.

Remember to not over think it. Just feel the conversation and spout reactions whenever everyone else does. Do not try to stand out. Try to blend in and be in step.

I did that for the longest time. And the more I did that, the more I got used to the beat of different conversations. And slowly, you'll learn when to input expected one liners, like "That's gross." and someone might turn to you and nod in agreement. And there, that's your first step to someone paying attention to what you have to say.

Then slowly, you'll get more used to the beat, and can experiment with longer responses, and see how long you can hold the attention. If you lose it, then you've lost it. Don't try to continue it. Look at where the conversation is and continue reacting till you feel that leeway to input another long response.

Also, learn to read different groups of people. Different sets of friends have different beats. There are times where people do look for a discussion and insight, but when you're in a group and having fun, people don't care too often.

There were times where I'll remember the different conversations, and think about them as I make my way home. It's like a review of what happened. What have I learned? That sort of thing. I'd think of what would have been a funny thing to say, or what would have been a good place to say this or that and try to remember to have this response next time this sort of situation plays out. Try to watch people and try to remember who likes what, who responses to what. This is when thinking deeply about the conversation might work. It's like homework. Learn the theory now, and apply the practical later (without over-thinking. That's what the theory portion is for).

Of course, as you get used to it, and am able to read the conversation and reply without over-thinking, you can slowly allow yourself into your head again, and quickly think (not over-think) of interesting things to say on the spot, ways to contribute or even steer the conversation a certain way, make people laugh, tell stories and eventually stand out.

This is what worked for me. I wouldn't say I'm a great conversationalist or anything, I'm still learning as I meet different types of people and flounder from time to time. But I'm much better with people now.

Although, having deep meaning relationships is a whole thing altogether. I don't know how to do that. Most of the people I know are colleagues and acquaintances (useful contacts, basically) when you have group outings and stuff. I only have about 5 close friends from school that I constantly meet up with.

I've accidentally rambled on for too long. I wasn't planning that. I don't know if what I did will work for anyone else, but I've gained a skill by doing this, and hopefully others might too.

TL;DR Stop over-thinking. You have to first attempt to blend in before you can start standing out.