Choose a known reference
The northern Peace Hotel building, historically Sassoon House, is identified in Shanghai's architectural guidance as an Art Deco landmark. Use a known example to establish a reference before applying the label to everything built in the same period.
Compare it with the former HSBC building at No. 12 on the Bund, discussed by the same guide in neoclassical terms. The point is not to stage a style quiz. It is to notice that neighboring historic buildings can make very different architectural arguments.
Read the silhouette, then the surface
Begin at a distance where you can see the building's outline. Follow the direction of its strongest lines and notice how its mass is organized. Then move closer to examine repeated shapes, the treatment of an entrance and the way materials meet.
An isolated geometric detail may belong to many design traditions or to a later alteration. The relationship between several features is stronger evidence than a single cropped photograph. When you are unsure, describe what you see before naming it.
Separate a date from a style
Buildings from one decade do not all belong to one movement, and older buildings can acquire newer fittings. A hotel interior, a shopfront and the structure behind them may represent different moments. Record the particular element you are discussing.
This also makes comparisons more enjoyable. Two entrances can share an emphasis on geometry while organizing arrival differently. A material can appear in several styles. The question becomes how a designer uses something, rather than which drawer you should put the building in.
Make an honest comparison
Choose two facades you can view safely and write down one similarity and two differences. Begin with ordinary terms: vertical, layered, curved, symmetrical, heavy, light. You can add specialist language when it helps explain a visible decision.
For interiors, check current access with the venue. Public-facing historic buildings remain working hotels, banks, shops or institutions. A heritage description is a source for history, not an entry ticket. Keep a street comparison satisfying in its own right instead of building an afternoon around an unconfirmed lobby visit.