Drawing buildings from atop is challenging for some. Here are some pointers that can get one acclimatized sooner to drawing this top down view.
Things that are farther from viewer appear to narrow. If 2 dimensions are getting farther from you, the ones that recede from you faster, narrow faster.
Uma
So, if you are top of a tall building, it’s base will narrow in drawing.
You can practice this by placing photographs and then physically tracing the silhouettes to prove it to yourself or to build a muscle memory in a gentle non-prescriptive way.
You can easily ascertain that the theory of perspective lines merging into a point holds. In this case, the buildings base doesn’t fall away from me as fast as the buildings along the streets do. See blue lines below.
Rate = distance / distance in the view of my picture. So if the building is 20 floors tall, across 3 inches in my photo below. Whereas the far off buildings are 1 mile away within 6 inches of my picture.
Here is another example of using perspective to tie down composition. Notice that the building tops seem closer to each other than their bottoms do.
Perspective Guidelines 
Finished sketch
