I was with a girl a little bit back who had never had an orgasm before. She had some body issues (it's INSANE how thw SEXIEST ones have the esteem issues) and just was never comfortable. She had a BF for over a year and never friggin had one.
You know what I did? Created trust and a comfortable environment. It's that simple. Also, I teased her and implanted very sexual thoughts in her mind here and there. She couldn't help but be aroused mentally, and once I got her comfortable, she finally had one.
And, let me tell you, being part of giving a girl her first orgasm is one of the best feelings in the world. She actually made me stop and just laid there, as if she just saw God. "Do you realize what just happened?!" panting, sweating, trying to catch her breath. SPEECHLESS