Hello! I'm Zero, nice to meet you. I don't feel that I have to give you the whole "I will critique you as nice as I can and please don't flame me for etc etc.", since you so often make wonderful critiques anyways, I'm sure you understand!
Thank you for being such a wonderful help to your fellow deviantARTists!

Let's begin.
I generally start with the good things first!

I love all the detail- Her folds in the skirt and shirt are really nicely executed. And her hair- Oh I love her hair! The wings, too.
You have a really nice grasp on anatomy.
Same with your composition- This piece is rather nicely balanced, though I'll get more into detail on that in a little bit.
Certainly, I MUST say something about these water colors! Absolutely BEAUTIFUL! I'm in the middle of a water coloring unit myself, in school- and these paints simply will not listen to me. I really am amazed- I'll have to take a look at that tutorial of yours!
Oh, and just by the way, I like how your signature doesn't distract from the picture.

Some things to note!

Though I do love her skirt clothing folds, value seems to be a little out of place here, but I'm not sure if that's her skirt design or the shading.
Also, while we're on the subject of shading, I would set a defined light- your shadows are a bit haphazard. I understand this is hard to do, especially since she's not anywhere in particular- meaning, the sun isn't your most obvious light source.
Ooh, back to that composition matter, I'd suggest cutting out some of the unnecessary blank space. For example, just above where her wings end and to the left of her skirt. But other than that, I really love how this piece balances!
She doesn't have much of an expression. ): She seems rather mellow, poor thing- this isn't really a bad thing, and I haven't seen too much of your work, but if alot of your expressions look like this, I would consider trying out some more emotions! They help wonderfully!
VERY VERY MINOR And It might even just be my monitor, but right around her bum area, more along the back of her hips, that color in her shirt seems a little out of place, like it is a 'happy' color instead of a 'sad' one! It's alot less grey, but, then again, this might just be my computer!

All in all, I really love this piece- It's so peaceful and sad, and I almost want to hug her and tell her everything is alright. Outstanding work!