This has nice perspective, mood, and negative space, but I can kinda see the brush tool shape from photoshop. Unless that is what you are going for, you might wanna blend it in a little more. My second notion is that with the light source in the back like that, the bridge should drop a shadow. Good work!
Usually, it's best to bring the smudge tool in when you've established a rough but fairly accurate (if you get what i mean) gradient with something more solid, and work with the smudge tool from then on, but i couldn't really be bothered on such a quick sketch here lol.