Look For Light
Different lighting can change the mood and feel of a shot, or be the difference between a mediocre and stunning shot.
The light from the setting sun can produce wonderful lighting for a subject, as does sunlight through leaves. Maybe you see a shaft of light between two large objects such as buildings that can be a perfect backdrop for your subject.
Other options for different light sources at night include :
Neon lights make great night time subjects. You can silhouette your subjects in front of them, or use them as a subject themselves.
Use a long exposure on a tripod to capture streaks of car lights on a road or highway, or other moving lights like on a ferry.