I'm Nicky Hilton. I live between London and NYC, take 3 baths a day, and always call my mom.

Winnie Au for BI This as-told-to essay is based on an in-person conversation with 42-year-old Nicky Hilton, the socialite and cofounder of personalized jewelry company theo grace, who is based between London and New York. It has been edited for length and clarity. I've been in the fashion world since I was 17. I studied at FIT, and, as a member of the Hilton family, grew up around the industry. I've worked with lots of brands, but theo grace, my personalized jewelry brand, is different. It's...