Just tell her how you like it, simple as that.
My girl loves to give me head, it gets her wet, but when we first started dating it would take her 20 min to get me off. With a little it of coaching and positive reinforcement she figured it out and knows exactly what I like.
Same goes for her, she let me know how to get her off when I go down on her.
Moral of the story, communication is key. Tell her what you want and have her do the same. A good sex life is essential in maintaining a healthy relationship.