If possible turn it away from the usual direction of rain and strong winds. Clothesline poles can be suitable if the box is located away from or above flapping clothes. Chickadees like to nest near bushes or shrubs. Purple martin colonies will probably not be used unless these birds already frequent the area. Wrens need two boxes, one for the nest, another to store nesting material.
Flickers adopt a nest box more readily if it is placed above surrounding foliage.
Wood ducks, goldeneyes, hooded and common mergansers prefer a nest box near, or standing in, water. Poles for nest boxes in water are easier to erect by chopping through ice during the winter. Protection Starlings and house sparrows are imports and early nesters that often take over nest boxes intended for native birds. If they become a problem, cover the entrance holes of the boxes until your desired species show up in the spring. Red and flying squirrels will think you put up the boxes for them.