Characterization is not divorced from plot, not a coat of paint you slap on after the structure of events is already built. Rather characterization is inseparable from plot.

Conflict is the place where character and plot intersect.

Technology is Darwinian. It spreads. It evolves. It adapts. The most dangerous wipes out the less fit.

Religious reverence for one's own job, even if the job is worth doing, is a sexual turnoff.

What characters do must grow out of who they are, and who they are is, in turn, influenced by what you make happen to them.

Anything said in upper-crust British automatically sounded intelligent.

Changers are characters who alter in significant ways as a result of the events of your story. They learn something or grow into better or worse people, but by the end of the story they are not the same personalities they were in the beginning. Their change, in its various stages, is called the story's emotional arc.