Change to Efficient Lighting First, don't use light unnecessarily . The best way to prevent light pollution is not to use lights in the first place. Before turning on a light or installing a new fixture, consider if you can do without. An attractive lamp during the day can be a harmful waste at night. If allowed so to do, the human eye adapts well to the dark - artificial light may not be needed.
Some lights are only useful in certain situations, but can be nuisances otherwise.
For instance, a homeowner might want an outside light for entering the house at night, or to see a potential prowler. But other than that, all the fixture would do is light the way for a criminal or bother neighbors. Such lights, especially security lights, are good candidates to use with motion detectors. Also, in most suburban areas car headlights are more than adequate to light the roadway - streetlights are unnecessary. The purpose of a street lamp is to illuminate the roadway, not blind motorists.