Personally, I've found there are 2 keys to having fun with RP.
Firstly, have a clear distinction in your mind when you are RPing and when you are not. Dipping in and out of character can be confusing to other people, so be clear when you're roleplaying. A lot of RP stuff is done just using /say rather than cabal channels, but if you want to make a comment out of character, then it's common to use two brackets ((like this)) or square brackets [[]]. That way you can clearly signpost if you're saying something as a player rather than in character.
Secondly, the key is about not caring how you act. People who know you will be able to appreciate that you're playing a character, and are not responding as yourself. If you don't know someone, then why worry about it? Tbh, most of the people in TSW see stranger stuff, and will normally just take it in their stride. If it's not being fun RPing with someone who's taking it too far, then you can simply stop playing with them. If they're in the cabal, then it may be worth having a private chat with them. It's possible that they don't know their actions are having that impact. If they do know, please let an officer know as we like to keep an eye out for that sort of thing 😉