In an industry as diverse as publishing, it’s no wonder that book marketing comes in all different shapes and sizes — which means that there’s a lot of differing advice out there when it comes to which actions to take. As a self-published author, you might be familiar with all of those lists that tell you that you “must do” this or you “must do” that if you want your book to sell, which can leave you pretty overworked, or (worse) paralyzed by the sheer number of things you’re supposed to do.

Most authors would be smart to focus on the few marketing techniques that have actually been shown to work — again and again. Without further ado, here are the four universal marketing techniques that I’ve found can benefit all authors.

Write a series of books

Sure, it’s possible to publish a standalone book and have it be a breakout success, so much so that it pays all of your outstanding bills and ends up being optioned as a blockbuster Hollywood film. But are the chances of that very high? Not at all.

The truth is that standalones are rarely going to reliably earn you a profit. If you’re aiming for long-term, sustained success, you should think about writing a series of books.

The idea behind this is pretty straightforward: if you manage to get a reader to become a fan of one of the books in your series, she’ll probably become a fan of the entire series — which means more sales potential for you.

This is the marketing tactic that you’ll often see romance authors successfully using to build an audience for a story universe. Book 1 in a romance series, for instance, might revolve around Main Character A and Main Character B (and Best Friend C will be introduced). Readers will become invested in all of the characters in the story — and, when Book 1 is wrapped up and the Happy Ever After is achieved for the two main characters, they’re told that Book 2 is about Best Friend C’s turn for love. Bingo: the reader’s hooked and the author gets another sale.

When it comes to marketing your series, it needn’t be too complicated. Don’t try to market every single book in the series and instead focus on heavily advertising Book 1 of your series in order to hook readers. How exactly you can go about advertising it brings me to my next marketing technique: book promotion sites.

Advertise on book promotion sites

The psychology behind discounting your book is much the same as that of any sale. (Think Black Friday or Cyber Monday). For books in particular, it’s much easier for a reader to take a risk on a book that’s free or $1 than, say, a book that’s priced at $4.99. This is especially true for new authors who don’t have a built-in audience yet.

That said, a discounted book will do you no good if no readers ever actually find out that it’s been discounted, right? That’s when book promotion services enter the picture.

Book promotion services are sites that send out regular newsletters to an (ideally) vast audience of readers who signed up specifically to discover discounted books. The more eyes that you get on your book from such a newsletter, the more sales (and fans) you might potentially get.

As an author, you’d need to submit your book for consideration and wait to be accepted. For some sites, this is easier said than done. BookBub, the biggest book promotion site out there, is infamously selective (and here are Andy’s recommendations on how to “crack the BookBub nut.” if you’re hoping to get your book featured).

Other sites are easier to grab a spot on, but might not have as big of a mailing list as you might like. Don’t be tempted by these smaller sites that don’t have much of a reputation: you might not get enough sales from them to recoup your costs. To save money, it’s best to submit your book to the book promotion services that are big and generally reliable, such as Robin Reads and Freebooksy, each of which can result in over 1,000 downloads of a discounted-to-free eBook in a genre such as Thrillers. MyBookCave, ereader News Today, The Fussy Librarian and FKBT produce smaller yields, but are also cheaper, yielding up to the same number of downloads per dollar.

Grow a mailing list

If there’s one big mistake that authors make when it comes to book marketing, it’s forgetting to have a mailing list.

“A mailing list?” I hear you asking. “But isn’t that so ‘90s?”

It’s true — email’s been around for a while, and it’s pretty much lost its novelty factor. But there’s a simple reason why it’s lasted this long as a marketing technique: it’s because it works. Having a customer’s email address on file is the best way you have as an author to directly reach a reader.

Picture it this way: let’s say that you sell 100 copies of your debut novel, which is great. That means that you’ve got 100 people who were interested in your writing — and will probably want to read the next thing that you put out!

Now, authors with a mailing list can easily announce their next book launch to these customers with a single email blast. However, an author without a mailing list has no way of contacting these 100 readers to let them know when another book is coming out. Simply put, those are potential sales gone down the drain. Not ideal, right? So your solution is pretty straightforward: get a mailing list.

The most popular email marketing service is MailChimp, but some authors find MailerLite or ConvertKit useful. Setting up your mailing list is a bit more complicated, but you can learn everything that you need to know in this free course on creating and growing author mailing lists.

Your mailing list might grow slowly at first, but don’t be discouraged. There are plenty of strategies that you can employ to gain subscribers and build a strong author brand. Keep at it, and you’ll have a much easier time when it’s time to launch your next book.

Spend time perfecting your Amazon keywords

If you self-publish a book, you likely want it to sell. And the chances are that, if you want to sell, you need it to do well on Amazon.

Amazon is the giant of online book retailers, so it’s a no-brainer for most authors to put their books up for sale on it. However, the saturation of the market these days is such that visibility on Amazon is tough if you don’t nail two key factors, which are:

1. Your book cover
2. Your Amazon keywords and categories

That you need a great book cover speaks for itself. Truth be told, audiences will definitely judge your book by its cover. (Don’t forget that it needs to be striking in thumbnail form as well, since that’s likely how readers will see it when they browse Amazon’s online shelves!)

Perfecting your Amazon keywords and categories when you publish your book is a bit less appreciated. It might get lost in the flurry of other things that you need to do in order to self-publish your book on Amazon, like converting your file to a MOBI or writing your book description. Yet it’s just as important, since the keywords and categories that you pick will determine your book’s niche — and therefore its discoverability among the respective audience.

The general rule of thumb is that you don’t want your categories to be too broad (your book would be lost in a sea of results) or too narrow (you probably wouldn’t generate enough sales from such a limited market). However, the technicalities can get more complicated than that, and nailing this down on Amazon is an art in and of itself.

Which is why it would be well worth your time to study up on how Amazon algorithms work before you self-publish your book. I’d recommend checking out David Gaughran’s Let’s Get Digital.

As with your mailing list, don’t give up: book marketing might be overwhelming in the beginning, but if you get it right, it will literally pay you back in dividends.

This post was contributed by Emmanuel Nataf. Emmanuel is a co-founder of Reedsy, a marketplace that connects authors and publishers with editors, designers, and marketers. Emmanuel dedicates most of his time to building Reedsy’s product and is interested in how technology can transform cultural industries.