I have had 3 books published with major houses, plus a number of journal articles, and manuals. Stay away from "Publish Your Book" vanity publishing places...you pay money up front and you are responsible for advertising, marketing, and selling your book. Some agents can be good; however, quite a few will charge a fee to "read and critic" your work before they even consider submitting a manuscript to a publisher--agents always require a percentage of your royalty as long as the book is being published & sold.
That aside...
A good publication to consult is "Writer's Digest" a periodic magazine. Articles plus names of agents, etc.
Only consider publishers that publish "your" type of book. The major houses won't even consider unpublished authors as well nitch items. A "minor" work usually only has a first "test" printing of 1,000 to 3,000 copies. If it sells well 1st year, they may reprint. Author usually gets about 10 free copies of book as soon as it is published, additional ones at a significant discount.
Consider those publishers that publish agricultural, self-sufficiency, and related books. Check names of publishers where books are sold at Farm & Ranch and/or Home Improvement stores. A small publisher that pays you royalty is better than nothing. Expect a 10 to 20% royalty. If you are not "famous" a publisher will not give you an advance.
Good word processing program with spell checker is essential. Manuscript preparation instructions are available from every publisher. Manuscripts are always double-space lines. Citations must be accurate, as well as correct grammar and spelling. Manuscript margins should be 1" on all 4 sides. Editors always require a book outline, author resume/vita, as well as one or more sample chapters. Expect it to take 6 - 12 months from manuscript acceptance to seeing your work in print. Unlike high school and college English classes, it is ok to use "poetic license" and other gimicks in sentences to effectively communicate your point. That said. Ok. You get the point..." No one sentence paragraphs. Make an outline to use before you write...revise as needed as the work progresses. Copy must flow from one paragraph to another. Also nice to have a "hook" at end of each chapter to entice reader to go read next chapter. Avoid LONG paragraphs that bog down the reader...at least 2 to 3 paragraphs per typed, double-spaced page.
Citations should be as (Martin, 2009) in the copy. Use APA reference style:
Such as: (Example...not a real book...lol).
Martin, W.T. (2009).
Instructions On How To Write A Book. Wellington, TX.: Running Arrow Farm. 100+ Pages.
Hope this helps some
Don't use fancy typestyles when you type manuscript. A good printer (inkjet or laser) is essential. Never send same manuscript several publishers at same time. Can take up to 3 months from submission to getting a response from an agent and/or an editor.
Always, always, write "to your audience" that may buy your book: words, language usage, writing style, etc.
There's a lot more...however, hope the above helps!