On technical merits, there is nothing I can suggest to improve this image. The silhouette is well defined, sharply focused, and the lighting behind the flower is very creative and pleasing. I do agree with the one commenter that the black around the edges appears to be a little excessive. I do think that the black is necessary for this image and should not be cropped too tightly, as it provides an anchor for your wonderful lighting affect. However, as presented it tends to overpower the silhouette of the flower.
Feel free to PM me if you have any questions regarding this critique.
Very good! I like that this was taken at sunset, some of the mid-day ones look a little cheesy. This is simply excellent. I love how clear it is too, I see talent! (Cough Cough ribbonwinner Cough)