Write your manuscript! If you’re a debut or unknown writer, you’ll almost always need a full manuscript before you begin the querying process. Once you have successful books and a readership, you can usually sell books with only a pitch and a first chapter.
Determine your genre and category. Publishing is cyclical–genres, themes, and tropes drop in and out of popularity pretty regularly. Publishers strategically publish books based on what’s popular and what will sell. Some genres are just harder to sell to publishers–like extremely long books, memoirs, and short story collections–but most genres will eventually have their time in the sun if you wait out the market.
Within genres, there are specifications to follow that makes your book more “publishable.” For example, different genres have prescribed word counts–romance novels are typically between 70,000 and 100,000 words. Fantasy novels are typically a bit longer. Books get shorter the younger your target demographic. Word count is just one aspect of industry standard expected in traditional publishing.
Prepare your submission materials.
Query letter – this is a one-page pitch letter of your project.
Synopsis – a summary of your book, beginning to end (one-to-two pages)
Samples – for fiction, this is typically the first chapter of your book. For nonfiction, it might be any chapter you feel is representative. There may also be specific requests from the agent or publisher, like a different number of chapters.
Find publishers and agents. The majority of reputable publishers do not accept manuscripts without an agent, so you will likely have to find an agent first. To find an agent, you might try looking at published writers in your genre–are any of their agents open to queries? This is an especially good option if you have a connection with that writer, as it can give you more context and a personal twist to your query.