The most difficult thing is to break the ice.

Once this is done, everything feels easy. The trick is to have a rough idea of what you'll say and just take the plunge. And practice.

We all fear rejection. Once you get past that fear, you realise most people are reasonable human beings just like you.

If you're curious about the topic, I recommend the book Rejection Proof, by Jia Jiang.

It is hard as fuck for me. But every time it happened (either me or other person starting) turned out a great memory on itself, or lead to great experiences right after. Still, I do it less often that I would like

There's some solid advice in here - especially around performative interactions vs genuine.

I was someone who was raised home schooled and it really altered my ability to communicate with my peers, which was something I had to really work on later in life. It surprises most people who know me when I tell them this, as I'm a pretty outgoing / gregarious person these days. It was a deliberate choice on my part, and I likely overindexed on it, leading to me now being highly social.

For those looking to do the same, I'll offer my own advice: how you engage socially depends on how large the audience is.

Small audiences (1-2 people):

If you don't know them: your goal should be to get them to smile without feeling threatened. A lot of people fail at that last part. Don't give someone a compliment like, "I like your pants" out of the blue - it may threaten them that you have alterior motives ("Are they attracted to me?", "Do they just like how my butt looks in these pants?"). Reframe compliments in a way that isn't threatening - ask them something instead like, "Hey weird question, but can I ask what brand those pants are? I want to get my sibling a birthday present and I think they'd really like those". It shows you see them as positive without it being a threatening interaction.

If you do know them: your goal should be to be interested in what they are saying. Find the topic that will stimulate your mind / get you excited to hear them talk more about it. Don't just gamify it and try to get them to talk more than you talk; that's an easy way to make yourself not look genuine. Dig and find gold - everyone has somethinig cool to say, it's your job to find that.

Medium audiences (3-8 people):

Be the facilitator. Don't butt in to get your own voice heard, butt in to segue to others who haven't had their voice heard. "Omg thats crazy X, hey Y you recently had something similar happen right?". Keep the flow going. Your goal should be to make everyone else feel like they've found gold in the conversation with new and interesting nuggest on a regular basis.

Large audiences (9-30 people):

These are basically meetings, and are the worst possible social interaction. Your goal should be to make these as smooth as possible and end them quickly so you can break to smaller sizes. Present facts clearly without emotion, keep things on topic so you can move past them.

Presentations (30+ people):

With this size you do the reverse of the prior size - the facts don't matter at all. Your goal should be to present emotions, not facts. Don't tell people what the % YoY growth is. Control how they should feel about the % YoY growth. This is the biggest #1 failure I see from inexperienced presenters - they aim to just present the info. People can read the info later - convey to them the emotion they should take away from the data. On every slide you have you should have a goal emotion, and you should reflect that emotion in your presentation. Look at any great presenter and you'll notice the same - they have the audience's emotions in their hands.

This is a really good post

I tried this in college, but just got ignored or brushed off.

I hate it when strangers try to talk to me in public (e.g., on public transportation, at work). I absolutely do not care what you have to say, what you do, how your day went, how many pets you have, what your hobbies are, or where you spent your holidays, and at the same time, in no way do I want to share any details about my life, not out of privacy or anxiety of speaking but out of sheer annoyance and indifference. However, most of the time I do not want to insult the person that tries to talk to me in any way, so I just stay silent and try to endure this torturous assault until I find a suitable moment to get away.

Smoking used to be a very effective social interaction catalyzer back in my young days.

I read in a couple of comments that you are worried about "bothering people". To be honest, don't worry about it, you can attribute sufficient life skills to others to simply tell you (verbally or non-verbally) in case they feel bothered.

I absolutely don't want random strangers talking to me and I cannot be alone.