Introverts are a tricky group of people to interact with. Socializing with them is different from socializing with those that are extroverts or ambiverts, mainly because socializing in general isn't too exciting (selective socializing is exciting though). Being an introvert myself, I've put together a short list of the basics when interacting with an introvert.
Don't approach suddenly or in a rushed manner.
We seriously might think you're trying to kill us. It's actually terrifying. Especially if you're the kind of person to have a resting mean facial expression. You're scary. Please stop. Slow down and smile. But don't look crazy.
Touching is forbidden.
Why do people feel the need to be physical (in social interactions) with those who clearly are uncomfortable with it? We don't touch you, so please don't touch us. Personal space is extremely fragile. Touching may or may not result in cringing, stiffness, and a deer-in-headlights look from the victim.
Avoid singling an introvert out.
Being terrified of being put on the spot is a widely shared trait. The center of attention is not where we belong. We will insert ourselves into a conversation when we are comfortable. Putting us on the spot is humiliating and makes us regret socializing (more than we already do) and encourages us not to do it again.
Forcing socialization is painful.
Many times, introverts are totally comfortable being a wallflower and spending time alone (or with an animal). There are hardly times when an introvert will feel left out, because he/she is likely alone on purpose. Don't feel bad. The worst thing you could do is make an introvert socialize when solitude is voluntary, and I'll tell you why in number five.
Socializing is physically, mentally and emotionally draining.
The fewer people there are to socialize with, the better. Introverts sort of lend their energy to the group while conversing or just listening. So bigger groups are exhausting, and it could take hours for an introvert to "recharge" from it. Crowds are painful. Keep the social gatherings to a minimum amount of guests or your beloved introvert may be uncomfortable or might not show up at all.
Speaking up isn't an option.
Though introverts can be loud, it doesn’t mean we want to be. Or should have to be. Raising our voices actually makes us uncomfortable. Our minds are loud enough, so our voices balance out with our inner thoughts. Please don't ask us to do something uncomfortable. We'll turn down future offers of hanging out.
Don't assume we're stuck up.
Just because a person doesn't show interest in conversing with you (or a group) does not mean he/she is stuck up. There's a good chance that person is an introvert and is mentally panicking at the possibility of human interaction. Internal thoughts usually go something like this: Hey, I know her. Should I say hi? No, she'd think I'm weird for going out of my way. I'll just pretend I didn't see her. Crap. Of course. She saw me. Wave or smile, wave or smile? Both, both is good. Crap. Why is she coming over? Please stop. No. Ugh.
Meeting new people isn't exciting.
If you've just met an introvert, he/she may come off as uninterested in befriending you. Introverts tend to stray from small talk as it's boring, but don't get discouraged from getting to know an introvert. Approaching them with small talk is bound to fail, so try starting off with a topic that has depth.
Keeping in touch isn't a strong suit.
Congratulations, you managed to catch yourself an introvert! Now don't get your feelings hurt when you're hardly spoken to and barely see him/her. It's not that introverts don't like having friends. Friends are awesome. But we're comfortable enough in our friendships to feel that constant interaction isn't necessary to keep it alive.
Plan to do nothing.
The best way to get to know an introvert is to make plans to do nothing. We like to just be. Doing nothing helps us open up because we're comfortable in a quiet setting. Doing nothing is probably our favorite thing to do. It's relaxing and energizing.