Be sarcastic, as well as observant. You needed to know the flaws of your conversers as well as your own flaws.
If you mean communication, then just be logically cold or negatively affront. Speak where it hurts. Strike them in their lowest by using facts, and a lot of silvery linings in between to make sure those venomous words seep deep inside their mental wounds. Scar them until their scalps start peeling off and bleed out all the confidence and rationality they have left, only to further plunge your fangs deeper and twist their insides out with your sharp tongue.
You need to know what gets them triggered but keep it chill enough not to cross the line. When they look like they’re about to explode you stop and do a reverse. Be sarcastic/cynic with humor and have a obvious joking attitude. You need to get witty and come up with creative comments. And say them at the right timing
Practise coming up with creative ways to insult people. Swearing a lot is effective for coming across as hostile and riling people up, but it's not sharp-tongued. Using specific and creative insults hurts people more. A lot more. Be careful using them. I think it's because common insults and swears are cliche and easy to throw out. People get the general mood of what you're trying to say, but they're desentisised to the words themselves. If you come up with something new and specific, it shows that you care enough to mean what you say, and people don't have a mental block against your words. It can sound very silly when you say it, but it's super effective. For example, I once got into an argument with my dad very early in the morning. I wanted to show him I was angry but I didn't want to fight with him all day. He hates swearing, so I avoided using any swear words. Instead I said (because he was about to leave for work), "I hope someone spits in your lunch." My sleep-addled brain thought that such a childish sentiment wouldn't bother my dad, but it became a big family drama and he didn't talk to me for 2 days. In hindsight, I should have just said "fuck you". It works best if you know your target's insecurities and fears, but you can prey on some common ones if you don't. Or you can just wish something very realistic and surprisingly upsetting on them. Also, these should really be said in a calm but very sincere tone. Some examples: Your mother cries every day knowing she brought you into this world. I hope every girlfriend you get realises she's a lesbian. I hope you fail all your exams. You tried so hard to look cute today. It's a shame you'll never manage.