|Hello from the Critique Club,
First, let me congratulate you on entering your first challenge. Your solid 5+ score indicates that you have a pretty good image overall but that it lacks some of the "wow" that the voters at DPC crave. First let's look at the B&W conversion of your challenge entry. The nun on the left has wonderful contrast, which was easy to achieve with the white dress and black habit. However, the nun on the right blends into the shadows on the sidewalk. I would suggest taking a look at fotomann_forever's wonderful tutorial on B&W conversion. I think if you use the channel mixer method and play around different color channels, you may be able help the nun on the right become more prominent.
My other suggestions require reshooting the image. First, having faces visible would strengthen your image's connection to the voters. I would suggest shooting from across the street, as this would allow you to capture their faces and possibly avoid the bright sun in the background. With out the bright sun, you would have an easier time with your B&W conversion.
Feel free to send me a PM if you have any questions regarding this critique. Now that you have your feet wet, keep entering challenges. I look forward to seeing your next entry.