As in any genre, one of a writer’s jobs is to read, read, read. By reading different romance novels from different houses, you’ll get to know which ones offer which types, and where your idea would fit best. If you don’t like reading romances, you won’t succeed at writing a good one.
Don’t worry about what’s hot in romance novels today – write what you want to write. If it’s a hot, steamy romance, fine. If it’s sweet and tender with no premarital sex, fine. If it’s an 1880’s cowboy romance, or paranormal with vampires, or high-powered executives falling in love, fine. There are imprints looking for all of these, so there’s no reason to write something you’re not comfortable with or that doesn’t interest you.
Go first to the publishers of books you like to read. Do an internet search for “writers guidelines (publisher name)” and it should come up on the first page. After you find a few of those, search for “romance writer’s guidelines” and spend a few hours browsing. You’ll find many houses, print and e-book, that you hadn’t thought of.
Different hosues have slightly different names, but the basic categories are:
The level of sensuality ranges from keeping everything behind closed doors to numerous explicit sex scenes. It varies from house to house and from imprint to imprint within the same publishing house. Your reading research (good excuse to buy more novels!) and the submission guidelines will tell you what’s allowed.
Many houses also have imprints specifically for the super-sizzling romances. Harlequin Blaze, Silhouette Desire, Spice, and Avon Red are good examples.
Romance novels vary between a simple 55,000-60,000 words up to an epic 150,000 words. Between 60,000 and 100,000 words seems most common.
In the best of worlds, your novel should be the length it needs to be to tell the story. But if there is a specific imprint you want to write for, you can always tighten the story or add another subplot to make it fit.
Sources: Guidelines from Harlequin, HarperCollins (Avon), Kensington Books, LionHearted, Avalon, Red Sage Publishing, and Imajinn Books.