It seems like you're looking for one of us to give you some sort of magic answer that'll make your fear of talking to girls go away. But trust me, after 3 years of searching "ways to get over shyness/sa" on the internet |I've come to the conclusion that there is no miracle cure.
Sadly, the most effective way to get over your fear of talking to girls is to..well...talk to girls!
There are some ways to maybe make it a bit easier:
-try having fake conversations with girls in your head to practice what you'd say.
-in karate we do this thing called "one step sparring" where one person throws a punch at you and you have to escape and counter. You can do the same thing. Visualize someone saying "hey how's it going" then come up with a bunch of replies that you can say to that. Practice this a lot so the replies become automatic.
hope this helps a bit