1. Don't follow someone on Twitter, wait for them to follow you back, and then immediately DM them with buy links and newsletter signups. See, when you followed them, they thought you cared about what they had to say. For a moment they were really excited to meet you! When you revealed that, no, you really only wanted to sell them something, that was an insult. And it hurt.
2. Don't follow someone, wait for them to follow you back, and then immediately unfollow them. You are literally telling them they're only a number on your follower-count ambitionfest.
3. Don't post a whole lot about a super secret project that exactly ten of your besties know all about--and refer to, and giggle and swoon over--while all the rest of us have no idea what you're talking about. This gigglefest doesn't make me want to know more about your secret. It only makes me feel left out.
4. Don't post something provocative, wait for someone to be provoked or push back even a little, and then drill that person into the ground. Especially don't get all your friends to chime in on how awful that person is because they didn't agree with you.
5. Don't imagine that you are the only or the best or the most knowledgeable, and for dog's sake don't condescend or patronize. Especially don't assume that strangers you meet on social media are always less informed than you are. Most of the people out there have brains and something to say. Maybe listen to them sometimes.
6. Don't lie, but don't be a hundred percent honest. See, the thing about social media is that it isn't real life. No one in anonymous social media land cares that you hurt, that you're scared, that everything is moving too fast and you can't keep up. The good folks out there will be uncomfortable if you admit vulnerability, the excellent folks will private message you (maybe), and the assholes will kick you while you're down. Assholes kick hard. Don't open yourself up for that. Text a friend instead. If you don't have one you can trust, DM me. I may not have all the answers, but I promise not to kick.
7. Don't mock. I mean, just don't. Mockery on social media isn't as funny as you think it is, and it's exactly why we can't have nice things.
8. Don't rile up your mob unless you literally have all the facts about a thing.
9. Don't pretend you've never made a mistake. If you said something doofussy, own it and work to do better.
10. Don't shit on someone else's cupcake. This guy I know used to have a tee-shirt that said "Your Favorite Band Sucks," and that's kind of the tone of social media sometimes. If you hate a Star Wars movie or a rom-com or a news story, it's okay to give your take. It's not okay to troll around looking for someone who actually likes or supports that thing and then proceed to inform them that their opinion is not as valid as yours.
Oh man, I could go on. And on. Social media is a mess, and I both loathe it and love it with all my heart. It has connected me with the people I love most in this universe, and it's also introduced me to some really awful humans. Maybe the best advice is what Mama used to say about medicine: don't take it on an empty stomach and don't expect it to taste good, but it might help you feel better some.