Kate Middletonhas a role that few people in the world can relate to — that of future Queen.

Although there isn’t an exact guideline that the Duchess of Cambridge can follow, Sally Bedell Smith, the author of several biographies aboutQueen Elizabeth, reveals the secrets for success in the regal role to PEOPLE in this week’s issue.

1. Be Humble and Discreet

“That is the essence of being a member of the royal family,” says Bedell Smith. “It’s taking a leaf out of the book of both the Queen Mother and the Queen, who has this extraordinary ability to combine a regal quality with a palpable humility.”

The author adds thatQueen Elizabethgives speeches rather than interviews, while the Queen Mother gave just one interview in her life — the day after she was engaged.

“That kind of discretion works because otherwise you open the floodgates and counteract the majesty [of the role],” she says.

John Stillwell - WPA Pool/Getty

ROYAL Netherlands 212896

2. Maintain a Consistent Style

“Princess Diana was constantly trying on new personae and new looks,” says Bedell Smith. “She was in this hall of mirrors where she was always observing how she looked and reacting to it.”

She adds, “The Queen and Camilla, Duchess of Cornwall have long adopted consistent looks and so has Kate.”

Kate Middleton.Chris Jackson-WPA Pool/Getty; Mark Cuthbert/UK Press/Getty; Karwai Tang/WireImage

kate-middleton

3. Know Your Causes and Avoid Controversy

Kate’s public life has centered around the well-being of children, from encouraging them to play outside to encouraging public attention on issues facing kids such as addiction, poverty, abuse and neglect.

“Kate speaks knowledgeably about her charities, and that indicates she is mastering her brief,” says Bedell Smith. “She and William have adopted causes that can resonate with a large portion of the population and haven’t sought to take controversial positions.”

9/23 Cover featuring Princess Kate

4. Embrace the Countryside — and Your In-Laws

Queen Elizabethand the rest of the royal family often escape London for one of their country getaways such as Balmoral Castle in Scotland.

“She grew up in Berkshire. That whole way of life is embedded in the way the royals are,” says Bedell Smith of Kate. “It is part of savoring the outdoors and appreciating nature. That sensibility came easily to her.”

Kate Middleton and Prince William.SplashNews.com

Duke of Cambridge and The Duchess Catherine William King’s Cup Regatta

5. Be a Supportive Spouse

“Kate is secure enough without feeling compelled to overshadow William,” says the author. “In the case of Diana and Charles, it was a contest. He had been center of attention, and suddenly this supernova arrived and was taking up the spotlight.”

Bedell Smith adds, “It would be easy for Kate to slip into the foreground, but she is aware and mindful of that.”

source: people.com