Try fingering and licking at the same time. Try flicking/pushing really hard with your tongue up and down on her clit, or in circles if that's what she likes.
Usually I do that with two fingers but sometimes you have to work up to that.
You can also try fucking her and rubbing her clit at the same time but that takes some maneuvering. Doggystyle is pretty good for access to the clit.
A good position is you entering from behind and her lying down on her stomach, you move up her back and move all the way in and fuck her good, playing with her tits or pussy as you go.
Good luck!