Choose the time period that intrigues you the most as the setting for your historical romance plot. For the story to work, you'll need to invest as much time in researching the selected era and locale as you do in establishing a believable and compelling chemistry between your main characters. Some possible choices include:
Colonial America
Victorian England
Medieval Times
The Civil War
The Wild West
Ancient Egypt
The Roaring Twenties
Define the characteristics of your leading lady and man as well as the circumstances in which they first meet. In addition to physical attractiveness, the hero is often a few years older than the heroine and may or may not belong to the same social class.
Examples:
She's the wealthy governor's daughter and he's the pirate rogue that kidnaps her.
She's a governess who has come to tutor the children of a widowed baron.
She's a princess whose life is saved by the quick-thinking stable boy when she falls from her horse.
She's a Southern belle who catches the eye of a handsome lieutenant in the Union army.
Identify the external and internal obstacles that threaten to keep them apart. These adversarial forces can take the form of other people such as their own families or romantic rivals; opposing beliefs; the drama of war; impending natural disasters; and past wounds--usually emotional--that hinder the ability to trust one's heart to the safekeeping of another. Outline the steps the two must take to overcome these obstacles through love, perseverance, strength, faith, sacrifice and compromise.
Consider how your fictional characters will interact with real-life individuals who lived during the time period you're writing about. Examples of this include their physical proximity to or employment by someone famous, fictitious conversations about current events of the day, and scenes in which the characters impart advice that might or might not be followed and which can be juxtaposed against what readers already know about historical outcomes.
Examples:
The heroine tells her brother she has a bad feeling about his new friend named Custer. He ignores her intuition and goes off to Little Big Horn.
The heroine tells her childhood friend, Susan, that women should have the right to vote in U.S. elections. Susan takes this idea and runs with it.
Gather your research materials before you start writing your novel. Utilize reference books such as "The Writer's Guide to Everyday Life in _________," a series published by Writer's Digest Books, to glean a sense of clothing, food, subjects of thought, courtship rituals and employment during various eras. Other comprehensive collections include "What Life was Like", a full-color series published by Time Life Books and "The Story of Civilization," an 11-volume overview written by Will and Ariel Durant. Bookmark websites such as The Costume Gallery Research Library, Archiving Early America and Eyewitness to History.
Give your historical romance novel a beginning, middle and end. Increase the danger at every turn, requiring your hero and heroine to take escalating risks to be together. Review existing books in this genre to determine the level of intimacy and sexuality that's permissible. This information also can be found in each romance publisher's submission guidelines on their websites.