This is a many leveled skill.
Having interviewed more than a few crooks, I can’t say that I read people consciously, but when I get that “feeling ” I tend to listen closely.
Physical actions and movements, little things that catch the eye, sometimes is takes a split second, others it takes years.
Some people never gain the ability, others seem born with it.
No matter how many articles I read about it, I still can’t put it into words well.