Look around, observe and think how things are layered in the real world, and then it’s easy to bring this perspective into your software tools.
When you realize that, it’s easy to make two different materials, and then with some masking put them together. The problem is that dirt isn't a structural part of the glass, it is a separate layer of materials.
For example, I received a question about how to make dirt on windows, as the person who was asking couldn’t get it right playing with roughness or bump. And after that, when we paint or make Substance textures, it is important to understand how materials are made in the real world. With tools like unfold 3D, it’s easy to do that. My tip is to get used to UV unwrapping because it’s fundamental for everything that will later be done inside Substance. So I think in the future it will be much more important for archviz artists to know how to make photographs than to know how global illumination works. There is much more time for color, compositions and making stories. But we cannot rely only on those, and current renderers are becoming simpler and much less time-consuming. The archviz market is strongly heading to VR and real-time visualizations. Also, some integrations with renderers like Corona or Octane in Cinema 4D would be great, something like we have for Unreal Engine at the moment.
With Substance, we can easily make some scratches or smudges which will give much more life to images in less time than any other software today. I think Substance is a big help in archviz and product design industries for photorealism, especially for some wear and tear, because nothing in real life is perfectly clean. I’m planning to do one full photorealistic Unreal Engine interior with the help of Substance Painter, which I’ll use for my Patreon tutorials. I’m currently working on a visualization of Zurich airport with a company from Switzerland.