Research publishers to find out which ones publish work in your genre and currently accept unsolicited material. Submit to only those publishers that handle your genre and actively seek new writers.
Format your manuscript according to each publisher's standards. Many publishers list submission guidelines on their websites. Also, remember to thoroughly proofread your manuscript so that it is professional.
Write a one-page cover letter, also known as a query letter, providing your contact information, a brief summary of your work and your qualifications, such as advanced degrees or prior publications.
Send your work and your query letter to publishers via email or postal mail, according to the publishers' submission guidelines.
Query literary agents in addition to publishers. Some publishers only accept material submitted by literary agencies. Follow each literary agent's submission guidelines when submitting your work.
Keep a file or list of the publishers to whom you have submitted your writing, what manuscript you submitted, when you submitted it and when the publisher promises to get back to you about your writing. By keeping a running list, you will know when to query about your work and you won't accidentally simultaneously submit your writing somewhere else.