The first picture at least has 2 probems. 1. Perspective 2. Background. The background is totally dark, which makes the contour of the building not clear and sharp. The best time to take a night scene is a couple minutes later after sunset. The bright but not shiny sky stands out the contour and it also helps making pictures look transparent.
Understanding about aperture, shuttle speed, focus, ISO, exposure compensation and flashing is very helpful to make a nice shoot.
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