Sometimes it is useful to use photo material as base for the design. On SYMPHOGEAR6X, the director wanted a futuristic version of an existing location of Tokyo, "Harumifuto".

Draw (or adjust) a perspective grid to help you draw your original buildings.

You can use the "FIND EDGES" plugin on Photoshop to help you suggesting details without drwaing all of it. Draw new buildings. There is no trick here. You'll need a good sense and a lot of practice.

Here's the final result