I'll give it a shot
1. I have difficulty finding the point of focus, I think its on the left side of the flower. I like the composition w/ the flower angled down to the bottom right. It seems as though a smaller DOF would be beneficial to help declutter the background.
2. Your white balance seems to be off a little bit, seems a little yellow. Compositionally, maybe taking a step to the left may make a little more interesting line across the pic.
3. I like the idea, the background seems a little busy. Since it's one of the brightest area's of the pic it draws my eye away from the subject. I like the DOF, but I would have liked to see the tips of the leaf.
4. Too underexposed
Hope that helps, you've got some great potential here. Keep up the good work