When you have decided to give urban landscapes photography a try, you have to bring along a wide-angle lens, telephoto (zoom) lens, polarizing filer and a tripod. You need a wide-angle lens to capture wide shots while you need a zoom lens to capture distant details, for example, the cross of a cathedral. The polarizing filter will help to darken blue sky and remove reflections from non-metallic surfaces. Needless to day, the tripod is for low shutter speed usage.
One of the challenges when doing urban landscapes photography during weekdays and working hours are the people and traffic. These two elements will inevitably be part of your foreground images. To avoid this, you can do it on weekends. However, this may not be possible all the time if you have other commitment.
Since we cannot get rid of these two elements (people and traffic), we might as well use them as part of our composition. As recommended by Practical Photography (Apr 07 edition, page 36 by Chris Rutter), one of the recommended approach is to blur these moving objects. For slower moving objects such as the pedestrians, you can use a shutter speed of around 1/8 sec to 1 second. Whereas for the fast moving traffics, you can try using shutter speeds of 1/8 sec to 1/30 sec.
When you are ready to shot a building against a blue sky, remember to put on your polarizer filer. This is extremely useful when the building is glass fronted. With the filter, it will help to increase the saturation of blue skies as well as reducing the glare and reflections from glass fronted building.
Another viewpoint you can consider is to shot upwards. This is a different composition and you can get rid of the people and traffic in you foreground. You will get some great shots from this viewpoint as well. You can see some upward viewpoint shots here [http://www.internetbizcenter.com/photography/index12.htm].
If you have been doing nature landscape photography, you might want to consider doing some urban landscapes photography. As you walk along the road everyday, try to look out for something that you can create a stunting and memorial picture. You do not need to go out far and get it. It is how you compose it.