Once a novel or a course in miracles is published it must be publicized to gain sales. (If you self publish a book of history for your immediate family, there is no problem. You just give them a copy and you are finished.)
If you have a publisher like Random House®, they will handle the publicity for you. You may have to go to book signings or appear on radio and television shows to hype the book, but much of the arranging and scheduling will be handled by the publisher.
The rule is that you never pay a literary agent because he or she is going to get a cut of your royalties. Actually, because of rising cost, some ethical literary agents charge for certain defined services.
5. Self publishing is very easy to do and the cost to publish a novel using a print-on-demand publisher can be as low as $100.00 of even free. A print-on-demand printer can publish your book in any quantity from your PDF file. Your word processor will probably create the PDF file for you. Also, if you use software like Adobe PageMaker, etc., a PDF file is easily created.
Here is one site where you can publish your book free directly from your word processing file or PDF file, etc.:
Self publishing companies can charge high fees so you must watch out for your interest. Lulu.com is safe and easy and, as I said, free.
With print-on-demand you do not need to start with 1000 copies of your book. The books are printed one or more at time on order.
Self publishers may offer editing services but some insist that you are the editor and you must make sure the grammar and spelling are correct before you submit your book files. I published four novels and found that I tended to overlook errors during repeated edits especially those inserted by my spell checker. That is, the spell checker overlooks or changes a word. For that reason, you may want to have a professional editor edit your book.
You can find such an editor listed in Writers Digest Magazine or on the Internet. Just make sure you know up front exactly what the cost will be and what the edit will entail. You probably don’t want an editor to rewrite your book changing the style from yours to his or hers. An edit for grammar and spelling errors should be sufficient.
If your book is nonfiction then you can easily identify a market. If your book is Feeding Your Praying Mantis, you have restricted your audience to those who have captured a praying mantis and want to feed it to keep it alive as long as possible.
I would say that the size of your audience is zip, but lets take a look with Google. I put feed a praying mantis in the search box and got 199,000 entries. If I put in the incorrect spelling of praying (preying mantis), I got 221,000 entries. (In comparison when I put Taylor Jones the Hack Writer in the search box, I got over 500,000 entries.)