Not bad.
For night photography you will probably have to use a tripod (or something to place your camera on) and M mode (use a low ISO, aperture of up to f8 with that lens and an exposure of around 6 seconds). I even had some nice results with the scn mode and night shot HDR.
Other than that, the best you can do is look at good night cityscape photos and learn from what they do right, composition-wise, and then try to build on that.
Also, I just noticed you have a couple nice primes. I think those would be better suited for night photography, since they are sharper and can be used even at lower apertures. (of course, this depends on the weather, if its raining or snowing, you have to use a WR lens)