Overshoot. With a disciplined approach.
Never show the client anything but your best work. Let them make their selections from that set. To do otherwise is to risk having to look at the turd they selected for the cover of the magazine for an entire month.
And, when someone tells you a low-paying job is good exposure, remember that in this climate you can die of exposure.
This is all great advice, Also keep in mind that when she's being critical, to some extent, it's not about your photos, it's because they're of her, most people get overly critical when they see themselves in photographs, even those who are very used to being photographed.
The photos aren't finished while they're on your camera, or when they're copied across to your laptop, they're finished when you've finished them, and it should be the finished shots that are chosen from, because anything else just isn't representative of your work.
That said, she's already used to being involved earlier in the process, so you're going to have to accommodate that.
Politely point out that these are not the finished product, allow her to throw out some images if she really wants to, that way she goes having had her input, and her views taken on board, and then go and finish the remaining images, and have her choose from those.
That way she's been able to feel involved, and get to veto some shots that she feels she's not comfortable with, and then she gets to choose properly from the glossy finished product, which she's much more likely to be happy.
