The histogram looks ok to me. It's basically telling you that the pic has a lot of very dark and mid-tones. But not so much in the semi-dark and light. (if that makes sense). The best way to get good at it is adjust the gamma (or lightness/darkness) setting in your photo software and watch what it does to the image. B&W images are easier than colour, so that's a good place to start.
What you don't want is large lumps off to the right or left. That usually means that the range has been clipped.
Good shot, by the way.