ok, i'm going to answer and then move this to BTS.
here's the thing, a lot of women need clitoral stimulation to orgasm. if your roughly using your fingers, or fumbling around, you're not going to hit the right spot with the right touch, for long enough.
this will take time.
lay her down and kneel between her legs. use your fingers on her, fucking her with them. use more than one.
with your other hand, lick your thumb, since a dry thumb against a dry clit might hurt. take your thumb an gently rub her clit in circles (or as close to circles as you can while moving your other hand in and out). make sure she is relaxed and feeling good and not drunk- alcohol numbs you and it will take longer.
let her know you want her to cum for you. eventually, she will.