It's not enough, when writing about an historical or fictional world, to just imagine the physical differences (oil lamps, horses) or cultural differences (harems, rites of passage), and then explore how those differences play out in a character's life. It's the intellectual differences, the things that create the equivalence of “future shock”, that I find particularly compelling.

This cartoon resonated with me because I so clearly remember my (irrational but visceral) outrage when I first encountered the history of the OED (Oxford English Dictionary), which began life as a series of handwritten or typed scraps of paper shoved into pigeonholes in a repurposed greenhouse. This, for a dictionary containing hundreds of thousands of entries and citations. I suddenly flashed on an image of the labor involved in the simple clerical creation and moving about of all that data in the absence of computers.

Somehow, the thousands of man hours to build the pyramids or dig a canal was something I took for granted, something I couldn't really envisage doing myself, so I have a certain distance from it. But I'm a computer-native, and I felt, to my fingertips, what the labor would have been to wrangle all the data for the OED over multiple lifetimes. That was something that hit home to me.

Make things like that resonate with your characters. Make your readers feel that.