Think of all the interesting reflections you can capture in a wet surface or a puddle. Don't forget to include surroundings in the shot along with the reflection. For the reflection of the still subjects use long exposure with the camera on a tripod stand.
Use the action-mode setting with fast shutter speed to freeze raindrops hitting a puddle, or a vehicle's speeding tires flinging water around. One can also try out shooting wet scenes beautifully with black-and-white photography.