From the Painting Guide: There's a lovely sense of sharp sunlight in this painting and of character or personality in the figure. Looking at it, I feel as if I've interrupted a conversation.
Things to consider:
Composition: It may be the way the photo is cropped, but the brown bit on the top right-hand side distracts from the figure. When the painting is framed, this will be aggrevated. The same could possibly be said for whatever her arms are leaning on.
Proportion: The hand is incredibly long almost longer than the head. Many people don't fit 'standard' proportions, but if this person's hands are really so long and elegant, maybe they should be the focus of the painting. The pose of the hand compared to the arm seems slightly unnatural; the dark band on the back of the arm draws too much attention and contrasts a bit too strongly with the rest of the arm. The shadow on it is, for example, much darker than that on the shoulder.