This piece really caught my eye.
First thing I want to say is that I love, looove, the way you used light and the contrast of value is simply gorgeous.
The brushstrokes look so effortless and at the same time so... well planned, they are so rough in most parts of the painting but so detailed around the face and the tears are so sharp and the neck looks so good *sigh*
Honestly I dont know what to point out that could be improved because this is a speedpaint so it's meant to look kinda undone. Overall the only thing I see that needs a little bit of work are the legs, the anatomy. Nothing looks off at first but somehow I think the legs are too rectangular and big if you compare it to the rest of the figure (Not that you can really see much of the body anyways)
So, I think you should work a little bit with the anatomy but honestly this is a speedpaint so it doesnt really matter, if it was a finished painting Im sure you would have fixed. Another thing that you could look into (although, again, I love the piece and what I'm pointing out are just stupid things that you COULD work on if you felt like it) the color palette, maybe if you played a little with different hues you could enhance a bit the mood of the piece, make it more... striking.
On the other hand, your perspective and value are so on point it hurts my heart, the texture of the dust in the light, the way her (I think is a her?) hair flows and shines...
Great work, and keep it up♥