Okay, since you want constructive criticism, I'll do my best and try to tell you what I think could be changed about this:

First off the head. It's much too small for the lovely body you drew. Elongate the face, make sure it's not so pinched.
Next, as Wayward says, the right eye is much too small; granted it should be a little smaller, but not too much.
On to the hand: the fingers are a little off, especially the first one. Usually fingers don't curve out like that(though it's really hard to get hands right. xD) It's not terrible, but it still could be improved.

There, now that that's done, I'll tell you what I like about this.

The body. You did a good job with the proportions and pose. Really, it's very nice.
The roses. Gosh, I don't know how much I've struggled with drawing roses, but you make them look so beautiful! <3
The coloring. Seriously, great job. Coloring can be harder then the actual line art, and I know that's where a lot of people screw up, so to see something as nicely colored as this is refreshing. =)

Anyway, I hope that helps and I'm sorry if I seemed to harsh.

-Drift