My tip is to try being a bit bold, at least until you start getting comfortable with playing antag. You’d be surprised with how well it could go even with little experience. Going outside my comfort zone as an antag is how I got more confident in playing them personally.
And you will of course fail a few times, don’t sweat it. Every robust antag you know has been there too you know. You also shouldn’t worry about people judging you while playing, most of them can appreciate you giving it your best shot regardless of of you failing or not.
last but not least. Have fun and don’t overthink it. As Bubblegum said, this likely wont be your last shot as an antag, so getting caught isn’t all that bad.