Personally, I think those are excellent. The sky in the first one is awesome. Also the streetlight in the last one is good. And in the second one, the fact that the buildings are diferent lengths away adds some depth to the shot.
I do not think you need much or any advice. They are looking really good to me. When I convert to B&W, the first thing I do in RAW is drop the temp for most outdoors shots such as these to around 2200 and then drop the saturation to remove the color. After that I drop a lot of other level till you can hardly see the pic and the bring it up with exposure comp. I guess I'm giving away my secrets here.