This is the funniest phase to me. I love collecting photos from many places and using them in my works.

 

So find three or four photos that have elements that you like in them (a specific building, a statue, an electricity pole etc.) and try to find where they would fit best in your already existing composition.

 

Of course you can use other photos to understand how to draw a certain objects, like for example a road etc.

 

Notes on copyright:

 

You can use photos that don't belong to you as long as you don't trace them and you don't make a copy (it becomes a derivative image). This means you can use them to pick elements from them and arrange them in a new composition, only using those elements as reference. Example: A brick wall from Photo A. A glass door from photo B. A bike against the wall from photo C. Plant vases from various photos.

 

You can also use this technique to come up with original designs for buildings (or anything else, really), mixing your favourite elements from many buildings into one.

 

(For this tutorial, I used reference from Google Maps. For copyright reasons, I'm linking the imagery directly to Google Maps, so you can see which shots I used.)