It can either be placed in close proximity to a Headquarters or in the range of another Construction Yard. Make sure to place them as far as possible from each other to gain the maximum building space out of them. It is also advised to place them in direction of the sea on water maps to enable you to directly build a Shipyard without another Construction Yard.

In normal cases it is advised to not build any buildings close to enemy units as their defense is significantly lower during construction.

A common Confederation tactic is to do the opposite of the recommendation above and place the Construction Yard as far as possible away from the water. The reason for this is to avoid a vulnerability of your buildings to water units like Alligators. If you decide to do that you should know that Alligators are still able to reach your HQ on most maps, meaning that it will probably be destroyed, forcing you to rebuild it somewhere else.

The upgrade for increasing the Construction Yard range is hidden behind a Vision Range upgrade for it which can be more useful than you think as buildings require you to have at least scouted an area of the map before placing a building at that location.