Meet The Washington Post’s Cristina Quinn, who is always game to try something new. She is your guide in “Try This” — a new series of audio courses from The Post that will provide quick, fresh and practical approaches to tackling the kind of hurdles we all face: how to sleep better, get the most out of our relationships, get out of our own way and more. Follow “Try This” now so you catch the first course when it drops Tuesday, Dec. 5.