the "Just be yourself!" advice is not going to help you.
talking to a girl needs to be like talking to anyone else. don't be scared of them, put them on a pedestal above you, or see any kind of rejection as really mattering at all.
If you want a girl's attention, you gotta be fun to talk to. It's the same thing when hanging out with dudes. if you want dude friends, you gotta be able to have fun with em.
Not gonna act like I understand women, i will fucking never, but if you're nervous, you're probably boring.
tldr; talk to em like dudes?