Get her to ride lots of whatever she likes riding best (whether it’s berms or rocks or singletrack) before easing into the stuff she finds more intimidating. Also to build up a bit of stamina – it all seems easier once you’re not struggling for breath all the time.
I say this because nearly three years after starting riding I am still struggling to clean a few things that put the fear into me when I first started – even though I do way harder stuff on sight now.
Oh, also, Ed Oxley does great skills courses – I went on one day course and it moved my riding on massively.