Using the police building from the Mighty B! cartoon Space Evaders as my model, I've worked up the blue pencil:
I don't like relying too heavily on the model... and you'll notice it varies pretty much. But I like that the perspective lines really help to define this building. The perspective isn't exact - it shouldn't be, it's a cartoon! - but there's enough to give it a feel of solidity. I encourage you to try it. Think of it as just a box with some steps and doors and windows and stuff. Not too hard but lots of fun.