Just to give you an idea of how much things have changed, I wrote this post back in Dec. 2013.
Basically, I did a quick search on "romance bundle" on Amazon, and I got 799 results. If you do that now, you will get 40,588 results. So you see just how much digital publishing (especially the indie aspect) has grown?
If you click this link, you'll be able to see just how many ebooks there are on the Kindle store. As of time of writing (05.27.2016), Kindle Store offers a little less than 4.5M ebooks. Crazy, right? That's the number of books people have to choose from each day.
BUT you don't need to think of them as your competition, though. At least I don't. My way of thinking is - you can't ever write as fast as your readers can read, which is why I'm always happy to recommend other books to them. At least they're still reading. At least they're still in "our" world. As far as I'm concerned, my "real" competition is other forms of entertainment (e.g. TV, movies, music, etc.) although honestly, I don't try to compete with those things, too. I have so many stories I want to share and need to write that I don't even have time to think about competing. All I care about is writing the best story I can for every release.
But I digress.
Back in 2013, there was this chart I used (data provided by authors from the forum I'm a part of) that gave me a good idea of how many copies a book had to sell per day to achieve a particular rank on Amazon. It wasn't 100% accurate but it was reliable enough.
Back in 2013, however, I would have probably ranked somewhere between #200 and #270, maybe even in the 1XX range.
But like I said, it's different now.
1. There are more books in the market. So even though your book's selling more or even the same number of copies each day, other authors may be selling more copies than you, which is why your ranking isn't as good as it was before.
2. You need to factor in pages read. Ever since Kindle Unlimited launched, I've given up monitoring sales ranking. I just don't know how to compute pages read, and I haven't yet heard of anyone who's been able to even come close to any kind of reliable formula (even if it's based on estimates) for this.
When I Hurt, for instance, is 110 pages long.
If 440 pages of the book were read (doesn't matter how many readers since Amazon is all about page count), then you could also read that as 4 copies sold, right?
Back in 2013, let's say that this would give me a ranking of #20.
Let's adjust this for 2016, and since there are more books now, I should have a ranking of anywhere between #30 to #40 (we're playing it really safe with this estimate). After all, this is what happened to When I Love (to recap: it's Top 600 now, but three years ago, it would have been Top 300 easily).
BUT GUESS WHAT? The ranking of When I Hurt today is #10!
3. Just because a book has better ranking than yours doesn't mean it's earning more. I've mentioned this time and time again, but I think it bears repeating. $.99 books only offer 35% royalties to authors while books priced $2.99 above earn 70% royalties. Of course, this doesn't mean I have anything against 99c books. Not at all. At the end of the day, pricing is just one of the 4 P's of marketing, and it just so happens that 99c pricing isn't part of my marketing plan.
Originally, I believed that poor new release rankings = decreased popularity = income drop, but it's not the case at all. My new releases are doing fine, if I compare it to the number of copies I sell on release day.
After doing more number crunching, it turns out that reduced organic visibility = decrease in backlist sales = income drop.
By organic I mean the way your book remains visible to readers even without the help of paid advertising. This is usually due to having your book show up on also-boughts and bestseller lists. Unfortunately, there's been talk on how the algorithms for also-boughts have changed. There's also been talk on how Amazon's been more proactive when it comes to advertising their own books (like those enrolled in Kindle Unlimited, Kindle World, and those that they publish like Montlake titles).
Whether these are true or not doesn't matter that much to me, though. They're outside my control anyway. The only thing that I - we - should focus on is doing what we can to keep our backlist alive.
In the past, it used to be that making Book 1 in your series permafree was good enough.
Now, I'm sorry to say that it's no longer so.
BUT...it's not all bad news.
I'll be experimenting with some stuff that other authors have had great luck with. So we'll see. Hopefully I'll have more helpful news to share next time. Fingers crossed!