As an adjective:
* The lone wolf stood at the edge of the pack, watching the others play. (Describing a single wolf)
* A lone light flickered in the distance, a beacon of hope in the darkness. (Describing a single light)
* She felt a lone tear roll down her cheek. (Describing a single tear)
* The lone survivor of the crash clung to the wreckage. (Describing the only survivor)
* He stood there, a lone figure against the vastness of the desert. (Describing someone standing alone)
As part of a compound adjective:
* The lone ranger rode into town, a symbol of justice. (Describing a single ranger)
* She lived a lone life, content with her own company. (Describing a solitary lifestyle)
* The lone tree stood tall on the hill, a silent sentinel. (Describing a single, tall tree)
* He was a lone warrior, fighting for what he believed in. (Describing someone who fights alone)
As an adverb:
* He stood lone in the crowd, an outsider looking in. (Describing someone standing apart)
* They lived lone, away from the distractions of city life. (Describing a life lived in solitude)
Remember that "lone" always refers to being alone or singular.