Urban photography is always more of a challenge for me than landscape. It's probably due to the fact that urban places are far more accessible than remote landscapes. With so many images on the web, especially popular destinations like Venice (Venezia), it's hard to walk through a street and say to yourself "this will be unique" because it most likely won't be. Sure, we can wait for the right set of clouds and lighting just like in landscape but I always feel that in most landscape shooting there are no "streets" to restrict the vantage point.
I'm pretty sure that there are many images of this particular canal but the perspective that I’ve used in addition to the processing and the laundry that was out at this particular day may have landed me a more unique look. I guess that in the end will be what differentiates images of the same street corner or urban scene from one another and is no different than landscape photography.
So do visit the same street more than once, on different times of the day and year to get changes in the light, angle of light, pollution, laundry, people walking etc. Kind of hard to do on destination that involve expensive flights! Maybe we should be photographing or own cities a bit more :)