telescope.com has a quick paragraph on astronomy. Below I summarise the important points with a few of my own suggestions thrown in.
Dark & dirty places
Set up on grass or dirt, pavements and buildings radiate the heat again at night and the air flow created by this can distort your image. If possible you might be able to make use of a public park.
Failing the above you might be better off going to the outskirts of the city and finding a nice dark hill and avoid as much of the light pollution as possible, but obviously this depends on your situation.
Telescope
This doesn't require a special telescope, you should be able to manage just fine with what your budget allows for.
Though a computerised mount can aid you plenty in locating objects, as you have fewer stars to use as way-points in light polluted areas.
Here is an example I found earlier - yes they are quite pricey.

Note: This picture and the mount in the link are NOT the same mount.
Try to set up out of direct view of a source of light, i.e street-light or porch light. This is because you will suffer from a lack of contrast, making it harder to view the objects. So dark spots are good!
Light Filters
A good, fairly cheap method*, for negating light pollution that I have found is to use a light filter, these usually just screw on over the telescope and filter out light of that wavelength.
However, a very important point to note is that light filters will also filter out light from stars, galaxies and star clusters, making them appear duller.
Light filters actually decrease 'sky glow' which is, in part, due to the upper atmosphere.
What these filters are best for is looking at nebulas
Nebulas emit light of a different wavelength that are not dulled by the filter and they pass straight through.

If you are not hoping to look for nebulas then I do not suggest a light filter, as this will also dull the stars.
Examples of which can be found here

*cheap relative to buying a go-to mount that is