I've never had an orgasm

Try masturbation to learn how your body works.. you could try vibrators, touching your clit and vulva in various ways, grinding against something.. most importantly, make sure you do what feels good, not what you think should feel good. 

Some girls get off during intercourse by incorporating their masturbation techniques in with it.. for instance, having you or your partner touch your clit, trying different positions and rhythms, having a pillow between your legs, etc. 

Lastly, relax. Don't try too hard for an orgasm or you might ruin it.