In one of her books on craft, Beginnings, Middles & Ends, Nancy Kress wrote:

Every story makes a promise to the reader. Actually, two promises, one emotional and one intellectual, since the function of stories is to make us both think and feel. . . . Thus, a romance promises to entertain and titillate us, to confirm our belief that “love can conquer all,” and to transport us to a more glamorous world than this one, where the heroine (and by vicarious identification, the reader) is beautiful, well-dressed, and ultimately beloved. . . . As a writer, you must know what promise your story or novel makes. Your reader will know. She may buy your book because it belongs to a genre that promises certain things . . . or she may come to your story without preconceptions, in which case she’ll form them pretty quickly from your characters, tone, plot, and style. . . . By the time she’s read your opening, your reader knows what you’ve implicitly promised. (Writers Digest Books, 1993, pp 7-8)

Looking at the first chapter of your novel, what are you promising your reader?

For example:
In my historical romance, I promise my reader non-stereotypical characters, an in-depth journey into Regency England and the Napoleonic Royal Navy, humorous repartee between the characters, and a wait-’til-you-see-what-happens-next “ride” as my two strong-willed characters run head-long into each other, both seeming to stand in the way of the other achieving his/her goal.