I'm trying to make a composite where the camera is facing the glass but focused on the reflection of the city or what is behind the camera. Are there any ways to make this more realistic?
A real photograph taken in such dark conditions would have a wide aperture, which means less depth of field. This implies that the window (and the raindrops) would definitely be unfocused, and possibly also the subject in the reflection. You can play with the focus of the subject so it at least suggests who we should see.
Another option would be to have the subject in focus, but the window again unfocused, and the city somewhat defocused.
There is water on the window, but the city isn't glistening wet.
There are some flares that don't quite make sense here. Are they reflections of the scene behind the camera? Were they part of the "wet window" image? There isn't any light source in the city image that would warrant these flares.