Here’s the answer in 3 simple steps …
1. Make your book the best it can ever be. Whether it’s fiction or non-fiction you have to work hard at it and this will involve writing and re-writing and more re-writing. This means learning your craft as a writer. It means research. You need to step into the viewpoint of your reader. Is your book interesting? Is it gripping? Has it got an important message? What other books are out there which say something similar? You’ll need to go through a tough editing process. Is every word spelled correctly? Check grammar and punctuation. Presentation must be perfect.
2. Send your manuscript out to publishers. How do you find them? Check out the books at your local bookshops. The publishers and contact details will be on the copyright page in the first few pages of the book. If you’re seeking a local publisher then head for the local interest section. Look at the books a particular company publishes. Will they be interested in your manuscript? There’s no point submitting poetry to a publisher that specialises in history. There are many books out there. Don’t forget you’re in competition of many would-be authors. Post your manuscript (some may accept email submissions, but always check first). Don’t make multiple submissions to different publishers as it’s not good form. Follow up with a phone call 3 or 4 weeks later if you don’t receive a reply. If your manuscript is rejected don’t be disheartened, move on to the next publisher. This will take time. Rejection is all part of the process. Note that most big publishers will only read submissions made through a literary agent so you may have to find an agent first. This can be pretty tough going too. If your manuscript is accepted by a publisher then you’ll need to sign a publishing agreement. Be careful here with the legal terms and conditions. Get professional help if you need to.
3. Getting published these days is like winning the lottery. Thousands and thousands of books are rejected every year. Many don’t even get read because publishers face a deluge of manuscripts daily. If you’ve decided that you simply must have your book published despite the countless rejections then self-publishing may be the only route. Nowadays ebook publishing is readily available and economical. There are providers such as Smashwords that will assist you. You may wish to stop there. Having your book printed was expensive in the past and meant holding lots of stock. But nowadays you can just print one book from services like Createspace. They also provide an online distribution network. You can find your own “on the ground” distributor who’ll get actual copies on shop bookshelves. But this means necessarily printing at least several hundred copies. This is not for the faint-hearted. Coughing out sum large sums of money means going into business. Unsold and damaged books will be returned to you. Take note that these distributors demand a steep discount, often more than 50%. Some bookshops will allow writers to approach them directly. You should also note that unless your book is a best seller or classified as “ever green” it will probably be pulled off the shelves after a certain time or the shops just don’t bother re-ordering. Book shops constantly want new books but shelf space is limited. This means churning books. Don’t neglect the “book talk” for its a fantastic and personal way of selling your books.
This is summary of how it’s done. There are many books and resources out there that can help you. There’s a lot of luck involved. Being well-networked is of great help. Being persistent though will help you achieve your goals. If your book never finds a home, never give up. Write another one. And then perhaps a few more … Good luck!