The detail, colours, highlights, style (you've got the style of her face down perfectly now, I've noticed you've been getting it exactly the same each time), I love how you apply the white ink/paint and I love how desaturated everything is. This is also my favourite painting you've done of anyone's hair so far as well, the detail is lovely and you can see the amount of care and attention you've given it.
The only change I'd make is to maybe fade the background into the distance with that white material you're using for the sky because it'll draw focus to her and it'll make the distance seem distant rather than flat. Don't fade out the whole thing, though, because then it'll seem flat again, just do the very distance and blend it into the foreground. You could also make it a cloudy effect to go with the colour of the sky which looks pretty cold and foggy.