Hi fuggy. Something as important as this has been taken from a book because I didn�t want to get it wrong - and you ending up with fried babies next year!! Here goes:
1. Put your box up in autumn or winter, so birds get use to it before the breeding season begins.
2. Fix your box on a tree, wall or garden fence, 1.6 - 5m (5 - 16ft) above ground level. Use sturdy nails or screws if attaching from a fence post, or hang from a wire if attaching from a tree.
3. Site the box in any direction between north and south-east to avoid strong sunlight, prevailing winds and rain. Try to tilt the front of the box downward a little to create an overhang that will keep out the rain.
4. Site the box out of reach of cats and away from perches that could be used by predators. Keep it away from a bird table or feeders, as the presence of birds feeding nearby will put off potential occupants.
5. If putting up more than one box, avoid siting them too close together as this may lead to aggression between rival males.
6. Be patient, garden birds may take a while to get used to a nest box, and you may have to wait as long as a year before it�s occupied.
7. Once the birds have taken up residence resist the temptation to look too often.
8. Every autumn when you are sure all the young have fledged, clean the box thoroughly, removing all debris and scrubbing it inside. Avoid strong chemicals, use boiling water to kill parasites, or lightly dust the inside with a natural insecticide, such as pyrethrum powder. Phew, finished!!!!