Make sure you have a genuine emotional connection with your subject matter and a sense of responsibility to your protagonists. Book writing is a long and sometimes grueling process, which demands an endless well of energy and enthusiasm. Torpor is contagious - if you're bored, the reader certainly will be too.
Natalie Livingstone
Map it out. Even though I wasn't writing a novel, I needed to map out a narrative arc for the book. My challenge was finding a way to tell the mistresses' stories in an engaging way, keeping an element of drama, while staying true to the sources. Make a plan of the book as a whole and divide it up into sections and chapters. I made detailed plans for each chapter and they prevented me from going off on a tangent.
But be willing to be flexible. Sometimes a theme or character, which initially appeared tangential, can become the main story after further research. For example, the book was originally about four of the women. It was only when I delved in the details of Augusta's turbulent and tragic life that I realized she had to be one the central characters
Sit down at your desk at the same time every day, turn off your phone and focus. Take a break for some fresh air or exercise at lunchtime. Routine and writing go hand in hand.
Don't linger over sentences or paragraphs that won't flow. I wrote multiple drafts of each chapter and came back to fill in the blanks.
Challenge assumptions. What we think we know about historical characters is sometimes little more than myth. Anna Maria, the first mistress of Cliveden, had a long-standing reputation for insatiability, sexual rapacity and cruelty, which turned out to have been assembled from scraps of contemporary bile and augmented by Victorian outrage.
Research is detective work. Stories about women's power and involvement in politics are often lost or overshadowed - be prepared to dig for information and read sources in creative, open minded ways to uncover an alternative narrative.
Be aware that what's missing from the historical record is sometimes more important than what is there. Augusta Princess of Wales destroyed all evidence of her involvement in politics when her husband Frederick died in 1751; but this destructive act tells us a lot about the position of women at the time.
Ask two intelligent friends whose critical skills you respect to read the manuscript and make suggestions before submission.
Good sources aren't just books and papers in the library. Experiencing a place is important for writing its history. A radio played now in the underground sounding room at Cliveden can be heard up on the terrace, just like the sounds of string music that drifted up from underground to serenade party-goers in the seventeenth century. Buildings are repositories of information, and their material clues help to link past and present.
The Mistresses of Cliveden: Three Centuries of Scandal, Power and Intrigue by Natalie Livingstone is published by Hutchinson (2 July, £25 Hardback and Ebook)