Hillary Clinton spent a lot of time practicing her facial expressions ahead of the debates

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That calm, collected smile Hillary Clinton pasted on her face whenever Donald Trump started to go off the rails during the presidential debates? That didn't just happen naturally. In an interview with People magazine, Clinton admitted she spent a lot of time perfecting her "listening woman" face before she took the stage. "It is something that I really was conscious of because this is the first time a woman had ever been on a debate stage in a general election," she said.

On top of those challenges, Clinton noted she was also facing an especially unusual opponent, and it was unclear "which Donald Trump or how many Donald Trumps would show up during the course of each debate." Clinton credited her "relentless" team — who she said was able to get "in the head" of what Trump might do or say — with cracking that puzzle. "A lot of this comes down to who gets into whose head," Clinton said. "It's like an athletic contest."

Watch the video below for more on Clinton's debate strategies — including how she prepared for Trump's unexpected presence over her shoulder at the second debate. Becca Stanek