Writers who are searching for the ideal home for the "babies" should realize that publishers are not a one-size-fits-all business. As you embark on your journey to find the right publisher, here are some tips.
What types of books does that publisher produce? Approaching a fiction publisher with your non-fiction book means you will probably be turned away. It doesn't mean your book wasn't any good. You need to research your chosen publisher. Check out their website. Look at their catalog.
Marketability -- In my mind marketability trumps all. Will this book sell? Sometimes marketability is difficult to determine. Do some research into your book's market. Be prepared to defend your book's potential sales. Publishing is a business. Again, your book might be well written, but that doesn't mean it will sell to a finicky and unpredictable market. So, do your homework. Pitch your book based on market statistics and facts. Please don't survey your friends and family. They are biased and not a good representative of the market.
Writing -- Yes, writing does matter. Flawed writing with great potential will still win. Not all publishers will work with the writers to help them, but most will provide an editor who can provide assistance. When we look at books at 3L Publishing, we look for the potential and ability to do the work. If we see the potential, we are very willing to work with the author, which is one of our specialties. We work with new and emerging authors.
Don't Burn Bridges -- When a publisher turns you down, always be polite and courteous. It is absolutely not personal. Like I said, publishing is a business. And like all business, owners are in it to make money and be successful. Whatever the reason the publisher says no keep your good manners. Maybe ask them if they'll be more specific. If not (publishers are very busy) accept it graciously. You never know when another idea might be a fit. Getting angry and taking it personally will not help your cause. If you keep on friendly terms with a publisher, their staff might be able to help you in the future. Burn the bridge, though, and you'll never get anywhere with them again.