I really enjoy powerful bullet-type vibrators and they definitely make it easier to come. I can almost guarantee that you are both too worried about each other's pleasure, and when you do that you are no longer letting things happen naturally.
Getting her in the right frame of mind is an important part of being able to give her an orgasm.
This works incredibly well to make her cum because you have the double stimulation on the g-spot and clit at the same time. Any thoughts? Other times I'll ask if I can be in a certain position, like asking to be on top.