Guys I might need your advice on this.
I've been with my girlfriend for over 6 months now and we're really happy, we talk about many things including sex.. but we're not having sex yet, but we're giving each other orgasms at least trying. The problems that while I'm petting her down there, (she is still wearing her underwear) she seems very happy with it, and I keep listening to her to see what she wants me to do, but suddenly she asks me to stop saying that she doesn't know what the next step is, she doesn't know what she wants me to do anymore so she can climax.
Well I've tried everything I can but no result(she doesn't like to use sex toys, and vibrators)

How old are the two of you?

From his profile:

hey, I'm lebanese 1989 born, engineering student

Is your girlfriend your age?

Well J_9 I'm 22 years old and she's 19
She has tried some alone but she still didn't get any solution for this problem

I feel you and your girl friend may need to go to her doctor and let them run some tests to see if this is a medical problem she is experiencing.

Your girlfriend is going to have to learn how to masturbate herself to orgasm. She needs to learn what feels good to you. Once she does this, she can teach you what feels good to her, then you can reach orgasm together.

J_9 hit the nail on the head,
She, at her own pace, should take matters into her own hands and find out just what works best for her. So many actually believe the porn they see and think all it takes is a few well placed fingers or a giant member and for a very small percentage this may be the case but remember, those who do it for a living are Actors.
It may take her a while to be comfortable enough to realize her full potential for pleasure but I personally would not worry about a doctor or such too soon, Just think how picky your orgasms can be, next time use the other hand and even though you know just what you like, it just won't be the same using a different hand