1. Your Amazon ranking has nothing to do with sales. Although many authors are obsessed with it and like to send out mass e-mails to friends and family when the number drops, unfortunately, all your ranking means is that people are looking at your page. While it might be argued that sales will inevitably rise due to more page views, the direct connection between ranking and actual sales is zero. It's not that your ranking is meaningless; it just doesn't mean your book is on its way to bestseller status.
2. Amazon employs scarcity tactics to get readers to buy books, and the impact on authors is that they think their books are constantly out of stock when they're not! If you see something on Amazon that reads--"Only 3 left in stock - order soon"--fear not. It's not true. It's possible, of course, that if you're traditionally published your publisher is low on stock, but usually that's not the case. And if you're a print-on-demand author, your book can never be low on stock; Amazon has endless access to endless supply. My best advice to authors is to start ignoring this inventory notice altogether.
3. Your Amazon reviews carry weight. An author I work with recently told me that 50 is the magic number of reviews that triggers Amazon to start paying more attention to your book. After you hit 50, you get more visibility on Amazon. I'm just relaying what I heard, but since Amazon operates on logarithms, this makes sense to me. Therefore you must get reviews! Ask for them at every turn, especially when your book is just out. Consider what incentives you might be able to offer people to review your book. Each review you get is like a rock being thrown into a body of water where your book is a buoy. The impact of all those little rocks will ultimately help your book rise higher and higher to get a little more notice. And we all need that--because the sea of books is vast and your book is one lone buoy. Bowker reports that in 2013, 458,564 books (print and digital) were self-published. With those kinds of stats, you shouldn't feel guilty at all if it comes down to asking (and asking again) for reviews.
4. CreateSpace uses Ingram's services to get its books to the trade. The reason this is an important note is because, if you're using CreateSpace to self-publish, you might also want to consider uploading your book to Ingram. Amazon wants all of its self-published authors to be Amazon loyalists--only on CreateSpace and locked into KDP Select (where Amazon exclusively sells your e-book)--but I believe that the more spread out you are the better. Ingram has better reach and a more streamlined system (which is why CreateSpace is using them). So use CreateSpace for whatever perceived benefit it has as an Amazon partner, and Ingram for everything else.
5. Publishers cannot control the "Customers Who Bought This Item Also Bought" feature, but you can. This feature is another of Amazon's logarithms, and it's all about the shopping cart. You can encourage your readers to buy a book you want to be associated along with yours, and that can get you linked up with a heavier-hitting author. There are workarounds to a lot of Amazon's formulas. Use them to your advantage.
6. Amazon is effectively cost-controlling your book. If you're a KDP author (self-published through Amazon), then you know that you get a much nicer cut (70 percent as opposed to 30 percent) of your sale price if you price your book between $2.99 and $9.99. I've said in previous posts that I think this is akin to price fixing. And even though countless people have made compelling cases to me about why they will never buy an e-book for over $9.99 (and I get it), it's important to note the power of Amazon's conditioning. We do not believe an e-book is worth more than $9.99 because Amazon has trained us to believe it's not worth more than $9.99. Nothing to be done about it; I just feel compelled to bring this up again.
7. If you see that your book is selling for lower than its list price, that doesn't mean you're going to get paid less. So, for instance, you might be selling your print book for $15, and Amazon is discounting it at their usual 20-30 percent off the list price. But then you'll see that one day--maybe for a day, maybe for a week--that they are selling your book for $9. In these cases, Amazon is undercutting their own profit, and you get the same payment from them regardless. Amazon is huge on price experimentation, and they price books at their own discretion. If you're traditionally publishing, you get whatever split your publisher is offering you AFTER Amazon takes its 50 percent off the top (based on list price, not what Amazon chooses to sell it for). So if your book is $20, Amazon takes $10 (unless your self-published and you set a lower discount). If you're traditionally published, your publisher gives you 7.5 percent of that $10 profit (in other words, 75 cents). If Amazon chooses to sell that $20 book for $7, that's their choice, and they do it all the time, eating the loss both on the list price and the shipping. Which is why Amazon reports giant losses year in and year out and why their business model is crazy and why you're right to feel confused by this practice.
8. You need to claim your book via Author Central. Many authors know this and somehow forget to do it. When you publish a new book, you must claim it. Claim books you've contributed to as well, if you can. Claiming books on Amazon is like collecting chips; you're building your little empire and making your bio page more robust. Amazon Central is an extension of your author platform and should be tended to as such. Update your photo, bio, and other information as regularly as you would your website.
9. The sales information tab inside Author Central is not an accurate measure of sales. When you go into Author Central, they give you access to Nielsen Bookscan ratings, a helpful tool. However, Bookscan is not a measure of Amazon sales, nor is it a measure of overall sales. It accounts for approximately 70 percent of through-the-register sales. It's not something authors can or should use to compare their sales against, though it can be a good general gauge for how well your book is performing.
10. Amazon is more author-friendly than they are publisher-friendly. This means that if you're an author, you're likely to get great customer service from Amazon, especially on the KDP side of the company. However, Amazon seems not to understand the limitations authors who are publishing with publishing houses face where their data is concerned. I've witnessed them make suggestions and recommendations to authors that simply cannot be accommodated by the author's publishing house. This can be frustrating to authors (and publishers), but Amazon is its own organism, not too concerned about needing to understand how other systems work because its own is so dominant. They have an Amazon-centric view of the book world, and expect authors to conform to how Amazon does things. The note here for you, authors, is to take advantage of this by using and exploiting Amazon's resources, but work with your publisher; don't work around them. And don't for one second buy into the idea that Amazon is "it." Yes, it's the number one online space for retail sales; but for most publishers, Amazon accounts for only about 30%-40% of total sales.
I'm sure there are things missing from my list, and I'd love to hear what you think all authors should know about Amazon -- the good and the bad -- given your own publishing experience.