In my experience it's a skill that takes time to develop. It's hard at first for sure. There are lots of different models out there that people using for visualizing software and architecture, sometimes they can be helpful.
A piece of guidance that helped me a lot was this: "when looking at boxes and lines, the junior architect looks at the boxes - the experienced architect looks at the lines."
A piece of guidance that helped me a lot was this: "when looking at boxes and lines, the junior architect looks at the boxes - the experienced architect looks at the lines."