First off, only bother to do this if you actually care about her and want to keep seeing her. If you just fuck her and then leave you'll cause her a lot of emotional pain, and she will tie sex to lots of negative emotions which can really fuck her up mentally for a long time.
The basic strategy is to work up the ladder and anchor each new step up the escalation ladder to the previous one she was comfortable with and enjoyed. So, let's say she ok with kissing and likes it, but feels uncomfortable with anything more.
1. Kiss her so she's enjoying it and getting horny. Whilst kissing, stroke her face, then neck. Move down and kiss her neck. Whilst kissing her neck, touch her boobs and play with her nipples. The feeling should anchor so she's now comfortable and enjoys having her boobs touched.
2. Next time, whilst sucking her nipples with your tongue, move down and stroke her sides down to her legs and inner thighs with your hands, really gently. Then kiss her all the way down her sides and kiss her from the inner thighs up towards her pussy, but not actually touching it.
3. Next time, whilst kissing her and playing with her boobs, stroke her inner thighs and go around and very lightly play with her pussy. Don't go for any direct clitoral stimulation though, just around the vulva and maybe some indirect clit stimulation.
4. Next time you can lick her pussy properly, try and get her to cum that way.
5. Next time whilst licking her pussy, insert one finger very gently
6. Next time, insert one finger and gently massage the upper wall of the vagina, just past the pubic bone, in a "come-hither" motion
7. Time after that, do the same but with the deep spot, towards the back of the vagina just before the cervix.
The last steps may take some time for her to be comfortable, and she may rely on clitoral stimulation, but you should be able to get her to become vaginally orgasmic, so when you get around to actual penetration, she'll really enjoy it. However, be warned - the first 3 times or so can usually be painful for her and she won't really enjoy it (even though she'll be so tight I'm sure YOU will!

However over time she'll get into it, and you can mould her into a happy, loyal sex slave who will likely love you forever!