First point - a watermark is not going to stop anyone from stealing your image - ever! If I wanted to steal your image, not that I would do that, because I am very strongly against that sort of thing, it would take me all of five minutes or less with Photoshop to remove the watermark. If, for whatever reason, you are going to insist on using a water mark, then, in my opinion, it should include a copyright symbol and a year, e.g., © 2012 Rizwan Satter. People may not be as prone to "steal" something that is marked with a © symbol - don't know(?).
As far as other compositional things go, I would have liked to have seen more sky, maybe the top third or quarter, as the sky that I can see has some very good contrast and tonal range to it. These are among the more inportant aspects of black and white conversion. I would also have placed the girl off centre, either on the left or right third line in the image - rule of thirds. Having her right in the centre, draws the viewer to the centre of the image and then the horizontal railings which are compositional horizontal lines, take the viewer's eye out of the image. If she is off to the side, then she acts as a vertical line to keep the viewer's eye in the picture.
WesternGuy