I'm very new to photography, so please feel free to discount my opinion as I'm merely basing it on what looks 'pretty'.
Her pose is very awkward, it would have worked better on her knees or stood up straight so you could see more detail of the dress she's wearing. Her hands are posed in very rigid way which doesn't look very dainty and is incongruous with the rest of the photo. You cannot see much of her face in this shot- it's all in shadow and her hair is covering it, therefore it is rather just a moment of something that happened, rather than a composed shot. The camera angle lets us look right down her top- which obviously if that was the look you were going for is fine, but she looks rather young and it feels more like her cleavage is on show by accident rather than intently?
Sorry- I hope that wasn't too negative and I really do like the colour of the dress and the way her hair is styled.
