"Mad Men" costume designer Janie Bryant and a new book to match. Photo courtesy of Maybelline.

In her new book, "The Fashion File: Advice, Tips, and Inspiration From the Costume Designer of 'Mad Men,'" Janie Bryant shares the clothing philosophy behind each of the gorgeous characters and then extrapolates how the ideas can be applied to everyday dressing.

For example, Joan's secret weapon is the pencil skirt, which practically guarantees a wiggle when you walk. The key to Peggy's character is in the color mustard, and Betty is all about the silhouette.

"It really is about knowing about what looks great on you all the time," Bryant shares with StyleList, "from the colors, to the shapes, to whether you wear a certain trend."

Bryant and Maybelline celebrated the launch of her book at The Griffin in New York City's Meatpacking District.

Besides Bryant, the guest of honor was her mother, Dottie, dressed in the MOD swing coat with shawl collar from Bryant's QVC collection.

"She's made me cry three times," the often emotional Bryant says happily.

As for dressing well, Bryant says, "I think it's about understanding your body and feeling great about whatever shape you are... learning to appreciate everything about yourself and wearing things that make you feel fantastic."

Speaking of fantastic, Bryant fit the bill, dressed in a vintage-y Dennis Basso dress, platform shoes by Ruthie Davis, and Miriam Haskell jewelry.

"He really let me go today, playing dress-up in all the furs," she says of Basso. "I just love this dress."

Speaking of dressing up, click here to find out Janie's favorite Halloween costumes.

And check out Heidi Klum's Halloween costume.