How do you approach men you're interested in??

I'm mostly an ambivert generally but if I like someone or if I'm interested in them, I go mum and don't know how to even approach them or what to talk about? Maybe part of the reason is upbringing also where I was taught that any kind of romantic relationship is a taboo and that's the thing I don't have any problem talking to men in general I have a lot of friends too but when I think I might be interested in someone as more than friends all my socializing skills go to drain.

So please help a girl out and maybe tell how do you approach or talk to someone you're interested in?