Most girls are very submissive sexually - fifty shades should be sufficient proof of that. I'm not breaking any ground here, but I find that thinking about dominant behavior as being capable of conforming to the internal question in the title helps convey it better (I'm personally a switch and ask myself that exact question when thinking about girls.)

Obviously, adapt it if the girl you're talking to is one of these femdom unicorns ;) But usually you need a lot less game with these as they tend to be forward, it's just a matter of not fucking up.

Hope this helps.