Nearly all authors, published or not yet, make at least one or two mistakes that, if it doesn't ensure failure to get published in the first place, it definitely hampers their ability to sell their books.

I know. I've made all of them at one time or another. As an editor and book publishing coach, I've also seen countless other authors make one or more of these mistakes.

We made these mistakes because we didn't know any better. You will know better, once you've read this article. That means you'll put yourself ahead of 95 percent of other people who will continue to make these mistakes. Knowledge is power, as the saying goes.

Mistake #1: Starting your book too soon.

While I'm all for taking action rather than just dreaming that "someday I'll write a book," most people get an idea and immediately start focusing on that idea. They never stop to ask some key questions, such as, "Who will read my book? What else is out there on this topic? What can I contribute uniquely to what's already out there? Why do I want to get this book published?"

In fact, there are twelve key questions I believe authors should ask and answer for themselves, ideally before they even write their first word. Thinking through key questions, doing some research on your topic and your market, will ensure a salable book.

Mistake #2: Not knowing who their audience is.

This one is very, very common. Many people want to write a book that appeals to "everyone."

"This is a book on leadership," says one client. "Everyone needs to know these principles."

Yes, but not everyone feels a need to know these principles. For instance, suppose you were working on a book about personality type and mothering. You could say that this book would appeal to any mom. Realistically, however, only moms who are motivated to understand themselves and others are likely to buy it. In writing up your plan (and the marketing plan of a book proposal), you would want to delineate key characteristics of the kind of mother who would be likely to buy this book. In addition, you might identify niche markets for whom the book would be of special interest--for instance, people who use personality type to counsel others, and any groups you may already have a connection with through speaking engagements.

When you know your market, when you can picture your ideal reader, it makes it easier both to write and market the book.

Mistake #3: Focusing solely on the book, and not considering what else they can do.

Now, this is only a mistake if you want to make money from your book. If you don't care if you make any money from all your hard work, then you can skip on down to the next point.

Seriously, most authors do not make any kind of significant income from their book itself. This is because a book has a perceived value of between $10 and $25. No matter how much expertise you pack into your book, the public is conditioned to pay only this amount of money for it.

On top of that, the royalty structure is such that an author will only make between a few cents to a few dollars on a book. The royalty amount a publisher pays is only around 10 percent of net. Net means what they get after they've given a retailer or other distributor their discount, typically at least 45 percent. If your book retails for $24.95, the net the publisher receives might only be $13.72. Your royalty from that would be $1.37. If you had an agent involved, they would get 15 percent off the top of your cut. That brings your royalty, per book, down to less than $1.17 per book.

Do you see now why you can't get rich on the book itself (or even pay your rent or mortgage)? You'd have to sell 1000 books a month--which is very unusual--just to make a little over $1000.

That's why you need to figure out other ways to package your expertise, and structure the book so that it is the beginning point of how people find out about you and get involved with you. Perhaps you can include an accompanying workbook, or audio products, or ask them to register online so they can get updates to your material.

Mistake #4: Trying to do it without help.

There's so much to learn about just about everything nowadays, that the only way to succeed in anything is to get help from someone who's been there, done that. Someone who knows the pitfalls and shortcuts and even where the likely detours are going to be, and how to get back on track.

Barbara Stanny, in her books Secrets of Six-Figure Women and Overcoming Underearning, talks about two kinds of helpers. There are the "Way Showers" who show you where to go and how to get there, and the "Messengers" who have the information, ideas, referrals and lead you need to get to where you want to go.

Look for Way Showers and Messengers from books, reliable online resources, and especially people you know who have already traveled the path. Don't know anyone? Seek them out. Don't be afraid to write to an author you admire or even an agent. We're all busy people , but most people like to help go-getters who reach out.

Mistake #5: Getting bad advice.

As you seek help, beware! There are many people who promise you that in a few days or weeks, you can finish you book and become a best-selling author. Be very wary of such claims. Check the person out thoroughly.

I once fell for a scam that promised to enable me to "Write a book in 14 days." Although there were a few interesting ideas in the program, it simply didn't work. The worst thing, though, was he never made good on any of his bonuses. I did check out one of his testimonials (he quoted a well-known copywriter I knew), but I should have checked him out further. The "master writer of 45 published books" had no known books mentioned in Google.

If anyone tells you anything other than that writing a book takes work and planning and that success, while possible, does not happen overnight--hang onto your credit card!

Mistake #6: Not having a good plan.

Most authors have no plan! You wouldn't build a plan without a blueprint, would you? You don't start out on a trip not knowing your destination, or without mapping your route, would you? Yet, many authors just think they can write their book and get it published without any kind of plan whatsoever.

I know. I've done it! I want to spare you the wasted time. Get the advice, devise your plan. Having a plan for anything makes a huge difference.

Mistake #7: Not writing a book proposal.

If you want to sell your book to a commercial publisher, a book proposal is indispensable. The only way you will ever sell a book to a commercial publisher is to send a top-notch book proposal.

Even if you self-publish, it's a great exercise to write up a book proposal. This becomes your plan.

I liken writing a book to painting a room. The most time-consuming part is the preparation: cleaning the walls, taping up the trim, then painting the trim. Writing a book proposal is like these preparation steps. After that, writing the actual book is as easy as rolling the paint on the walls.