The four essential qualities of a best-selling book are easy to understand once you know what they are.

And, you don’t have to have all four essential elements to make a best-seller. You could have as few as two out of the four. But if you have all of them, you’ve got a home run.

Here’s what they are.

1. A great idea

A great idea is essential, but if you have a huge platform, you can actually get a book deal with an idea that’s not yet fully formed.

But remember that it’s much harder to write a book based on a half-baked idea. It brings confusion and doubt during the writing process.

So, it’s always better to test out and develop your idea before you dive into  writing the entire book. Or, hire a professional to help you figure out what your idea is.

Of course, if you don’t have a huge platform you absolutely need a strong idea.

2. Great writing.

Compelling writing is always a winner. These days it’s getting rarer. But it can still sell books by first time authors. It has that power.

If you don’t feel confident in your writing you are not out of the running. You can hire a ghostwriter to write the book for you, or a collaborator who will write alongside you.

Or, you can write a strong developmental editor who will fix the flow of your ideas, paragraphs and sentences.

Investing in these things is a smart way to get your book done well and faster than you could in your own. Think of them as wise investments.

3. A great platform.

Many big publishers will pass on a great idea and great writing if the author has no platform or a small platform (numbers generally under 10K followers and no celebrity backing).

Sometimes even the promise of a great platform is not enough to land a deal. They want to see engagement now.

Other publishers will gamble on the hope of a platform, but the advance might be lower.

4. Great timing.

Timing is always a wildcard. We don’t know what’s on publishers’ lists or what’s forthcoming from movie houses and other media in your subject area. We don’t know what social or political developments are coming.

For example, J.D. Vance’s memoir, Hillbilly Elegy, about growing up in Appalachia, got a huge push around the 2016 presidential election. People wanted to understand what was going on in the rest of America, and Vance’s book helped to explain some of it. His book was on the best-seller list for a very long time.

So timing is key, but not something you can control.

Still, knowing about conditions that tend to create a best-seller helps you not only to craft a great book, but also to think strategically about it.