It's always about probing for consistency, congruence, and naturalness. You're never going to be able to spot every lie every time, only individual lies. For example, most women and a few men are able to act improv, that is lie fluidly without hesitation. It's only if you know directly what they're saying isn't true or after asking deeper questions that it becomes apparent if they don't know what they're talking about or begin to contradict themselves.

As my grandmother used to say: "One lie leads to another. Tell the truth because lying is too much work." I would also add that getting caught lying severely destroys trust and so isn't conducive to society either.