The lack of subject matter is the reality for architectural visualizers. While a photographer creates art from what's available in nature, the architectural visualizer is faced with having to create everything from scratch, just like a film or stage designer. So, what will you show when you can show whatever you like?
Close-ups of the building facade or views of the whole site?
Worm's-eye view, a person's eye level, or aerial view?
Photorealistic or artistic watercolor?
Animation or stills?
Flyovers or walkthroughs?
Shadow studies?
Sections through the building, individual wings, or phases?
It's a bewildering array of possibilities, and the temptation is always just to launch in and start building.