Small, everyday style habits can quietly shape how old—or how alive—you feel, both in the mirror and in your mind.

Read an excerpt from fashion influencer Lyn Slater’s book “How to be Old,” and learn how her sense of style has influenced the fashion world.

At age 66, when I look in the mirror, I may not see a 46-year-old staring back at me — but, perhaps, someone closer to 56. Maybe it’s because I’m so lousy at sitting still.