Place somewhere that is out of reach of predators and sheltered from the weather.  Should not be placed adjacent to bird tables or other feeding devices.  Do not disturb nest box once it is in use until fledglings have left the nest.  Thoroughly clean the nest box in early October as it likely will be used as a winter roosting site.  Nest boxes are most likely to be used if there are several placed around your yard.  Bluebird boxes should be sited  on open ground at least 200' apart.