I have a friend who was in the same boat as your gf. She hadn't ever had an orgasm. My suggestion is she needs to play with herself, alone. Until she figures out what it is that does it for her, almost nothing you will do will take her there. YMMV, but in my experience most women have their first orgasm by themselves when they are just exploring their body.
I find that when I am stressed or worried about something it makes it exponentially harder to orgasm. If her inability to orgasm is a big deal then it will take a very long time for her to get there since she is constantly worrying about getting there, and not how good everything feels. How old is she?
Oh, and the reason I suggest she plays by herself is that it should remove the performance anxiety she is probably having. After all, if she tries and doesn't get there, no one has to know. I also suggest
one of these.
This one in particular looks good as it has a dial to control the speed. As long as she starts slow she should have fun.
