Presence or absence of mobile phones, types of same. Straightened hair is another one, hairstyles generally (I like old B&W movies, which sometimes helps). Yes to face masks. I'm getting a bit better at cars from ca 1940 on.
And always zoom in - that factory visit one yesterday that in one way could have been any time from 1930 on, but a picture in the background had floppy-hatted, bare-midriffed, bellbottom-trousered young women admiring a big TV set and they got me within two years. Still not sure whether the man with the natty suit and cufflinks under his overall in that one was Nicolae Ceausescu. Certainly looked a bit like him.