how do you increase commercial demand in simcity 4?

Answer 1

Like residential, commercial buildings hate pollution and trash. Placing parks and trees can lower air pollution. Make sure to have a landfill to ensure that trash stays off the streets. In addition, commercial requires customers. Placing commercial zones in areas of high traffic ensures that they will stick around and be happy. Commercial buildings develop well near tourist sites. Placing a landmark near commercial zones helps businesses grow. The quickest way to determine the reason for your current desirability level is to query the buildings in the area. Using the Query tool, either hover over a building to get a quick glimpse of the most important information, or click on the building to bring up a dialog with detailed information.

source:http://simcity.ea.com/tipstricks/tipstricks_development.php