When we take architectural pictures, we want to have the sun shining from the side, because this accentuates the edges. In the old days, this meant a shoot took two days, one to visit the sites of the buildings of interest to determine the best time, and a second day to do the actual shoots in a tour taking us to each building at the best time.
Today this is much easier. We can use an online tool like SunCalc to determine the best time.
In the box at the top left you enter the shoot location, then on the horizontal time scale you simply drag the orange dot. On the map, the thick orange segment indicates the sunlight direction. Just move the orange dot on the slider until the segment hits the façade more or less perpendicularly. You can enter the data into a spreadsheet, which you sort by the time, to get your itinerary.
By they way, the thin orange curve is the current sun trajectory, and the yellow area around is the variation of sun trajectories during the year. The closer a point is to the center, the higher is the sun above the horizon. The colors on the time slider above show sunlight coverage during the day.