During the 10 years that Paul Burrell served as her butler—both at the Waleses' country estate, Highgrove, before she and Prince Charles separated in 1992 and in her own apartment at Kensington Palace—Princess Diana was host to countless private dinners and parties and developed a flair for entertaining with sensitivity as well as style. "Many people were intimidated by coming to [Kensington] Palace, so she often opened with a joke, probably at her own expense," Burrell recalls. "She would come into the room and say, 'I couldn't find a thing to wear!'—obviously a joke, because she had plenty of clothes. It was a matter of putting people at ease."

In his just-published book, In the Royal Manner: Expert Advice on Etiquette and Entertaining from the Former Butler to Diana, Princess of Wales, Burrell, 41, shares more of Diana's party tricks, along with a sampling of her favorite recipes and some memories from their days together. "She would lean over the banister and call to me in that high-pitched voice, 'Paul, are you there?' " he recalls. "I would bound up the stairs with enthusiasm for whatever greeted me."

Burrell admits that the princess, whom he describes as a perfectionist, would sometimes lose her cool with the staff. "There were times when things were a little fraught," he says. "I think you would not be normal if you did not raise your voice. She said it was her way to let off steam. And she would always apologize."

A butler who knew his stuff long before he met Diana, Burrell also includes tips in his book—everything from flower-arranging and napkin-folding to dealing with "difficult" food—culled from his 11 years of service to the Queen. (Whitebait fish, for example, "are cooked whole and eaten just as they are—eyeballs included!" he notes.)

"It's an informative guide to a year's worth of entertaining," Burrell says, not an attempt to cash in on his inside knowledge. "I was concerned it might be misconstrued," he adds, "but it is not a betrayal of any trust. This book shows readers how to create elegance in their own homes—style and elegance should not be solely the preserves of the rich and famous."

The author himself was hardly to the royal manner born. The son of a Derbyshire truck driver, he joined the Buckingham Palace staff in 1976 at age 18 as a household footman, moving on a year later to become the Queen's personal footman, then butler to Charles and Diana, and finally—famously—butler and close friend to the princess alone until her death in 1997. The fund-raising events manager of the Diana, Princess of Wales Memorial Fund until last December, Burrell now lives in Farndon, Cheshire, in the west of England with his wife, Maria, 45, and their sons Alexander, 14, and Nicholas, 11. He'd like to write another book, about the anti-land-mines crusade so dear to his former boss's heart, and perhaps work in television. One thing he won't do is sign on as a butler (he says Tom Cruise and Tom Hanks both approached him about possible employment). "A butler is anonymous, and I have lost my anonymity," Burrell says. "[Besides] I looked after the best. How could I top that?" Burrell talked to PEOPLE correspondent Simon Perry about entertaining royally.

What is the most important thing you have learned about successful entertaining?

The princess always said to me, "People matter most." So it's important to have a good mix—a few of your chums to jolly along the atmosphere, an extrovert to be the party's life and soul. I remember parties with Elton John in one corner, George Michael in another and designer Catherine Walker in the next room. The princess would invite people like that—high-profile, public personalities—because they would also help her entertain her guests. But of course celebrities are not the essential ingredient of a successful party. It is all about people.

Is there a magic number of guests that works best?

No, but beware of one-on-one lunches, which can be difficult—rather stilted and stiff unless you know the person well. There's a well-known male media personality who has the honor of the quickest lunch ever at Kensington Palace. He came and was dispatched within an hour because the princess found him boring.

So the princess avoided one-on-one meals?

She sometimes hosted them as getting-to-know-you sessions. Hillary Clinton came, Barbara Walters came, and those were good, chatty, informal times. When Oprah came, she understood the restrictions imposed on the princess in her life and told her, "I completely understand—that happens to me." I was included in the conversation too. The three of us got on like a house on fire.

Did the princess often throw large, formal parties?

No. Unless it was for a charity. She always hosted a party at Christmas to say thank you to all the tradespeople, to the charities of which she was patron. Those were for 200-plus guests and were catered. She only had a small household staff. We couldn't possibly cope with that. So my role at such functions was to keep an eye on the princess. If she needed rescuing at any point, I'd jump in and say, "Oh, can I introduce you to so-and-so?" And when she decided to retire, I would follow her back into her apartment.

But the party would continue?

Yes. The princess would insist that everyone had a good drink and made sure they weren't driving.

Is there a nice way to tell guests that the party's over?

The best solution if your guests are lingering is to subtly ask if they would like a coffee at the end of the evening before they go or whether you can order them a taxi.

What were the princess's private Christmas celebrations like?

The tree at Kensington Palace was 14-ft. tall with a star or an angel on top. I did the top half, and the princess and the boys [Princes William and Harry] did the bottom half. It was always silver and white, with white lights and crystal ornaments. The boys would be with their father at Christmas—the princess insisted they spend the holiday with their heritage—so we had a little mini-Christmas a week earlier. We had a lunch of roast turkey and plum pudding, with hats and streamers and balloons and presents. When Dec. 25 came around, though, her apartment at Kensington Palace was eerily empty. Until her last Christmas, 1996, that is. She lit so many aromatherapy candles in her room that she set off the fire alarms. In moments, five fire engines, each with five men onboard, drew up. You can imagine what delight the firemen had in seeing the princess wearing a gray track suit on Christmas morning. She thought it was hysterical—and it made their day.

After drawing up a guest list, what comes next in planning a party?

Planning the menu. Choose food that would appeal to many people rather than a few, and check with your guests. They might have a nut allergy, they may be a vegan—you should find out. Generally, a fail-safe menu for a luncheon or dinner is fish cakes in lemon sauce followed by roast beef. You don't want to embarrass your guests by giving them something too difficult to eat.

Such as?

Well, asparagus is difficult and messy. You shouldn't be afraid to pick it up with your fingers—it's done in the very best of households. But do not eat the whole thing, only two bites. It's good breeding to leave the last inch of a spear on your plate.

What other foods can be tricky?

Spaghetti can be hard. You should turn it around your fork, take a mouthful and let the rest fall back onto the plate—do not slurp and suck. And I would try not to give guests full-bodied prawns. It's not very pleasant to see someone pulling off heads and tails and undressing a prawn in front of you.

Do any desserts qualify as dangerous?

Don't, for goodness sake, prepare a soufflé! I remember an orange soufflé that collapsed before it got to the table at Kensington Palace. The staff had to do a quick rush-around, all hands on deck, to prepare a fresh fruit salad. When we presented it, the princess looked up at me with those eyes and smiled as if to say, "Well, something happened, but you've obviously averted a disaster."

What's a safer bet?

Pears in port wine with homemade cinnamon ice cream is elegant and easy. It was the princess's favorite. We served tiramisu to a lot of people because it's light, good for ladies' lunches. For men, especially in the winter, we'd serve something more solid. Bread-and-butter pudding with bananas is a favorite in royal nurseries. The princess liked to serve it to gentlemen in particular because it's a solid, honest pudding, and it's very meaty.

Once guests arrive, what can a host or hostess do to make them feel comfortable?

Relax—no one likes to see a stressed host. Greet your guests warmly with a smile. Settle people down and offer them a drink. The princess wasn't particularly fond of drink—instead, she would dash into the kitchen for a quick glass of carrot juice to help her nerves before a party—but she appreciated the fact that she had guests who enjoyed good wine.

Is the seating plan important?

When possible, it should be boy, girl, boy, girl. And if the table is square or oblong, you as host should sit in the middle, not at the end. The Queen or Diana would always sit in the middle. You are not lord of a manor.

How do you deal with guests who become boisterous?

Stop serving them drink and have a quiet word with their partner. It is better to let the partner deal with it. Don't tackle the situation personally, as it may cause offense.

What do you do about spills?

Just mop them up with a cloth if they're on a bare table. Obviously, you can't whip off a tablecloth if there are 10 people sitting round the table, so if, say, red wine spills, mop it up with a kitchen towel, sprinkle on salt to absorb the moisture and wash the tablecloth later. Don't panic and make a fuss—it's not the end of the world.

How should guests deal with food they don't like?

It's very offensive to leave it. Instead, cut it up, move it around the plate and look as if you're eating it. You could always lose a little in your napkin, but that could lead to a very embarrassing situation. Or you could give it to the corgis. That's an interesting tip—have a furry friend under the table.

Other than appearing to enjoy your food, what else makes someone a good guest?

Being punctual, although it is acceptable to be 10 minutes late. Being animated—having a couple of small stories to tell at the table. Writing your host a thank-you note afterwards is important too. The princess had her envelopes addressed even before a party. She always used to say people don't say thank you enough, and she was right.