One of the most important things to remember when promoting your audiobook is always to provide the link to the purchase site. We live in a world of short attention spans, and you want to catch a listener's attention and give them the avenue to download your audiobook right then.
When posting on social media, always make your link a clickable one. Don't expect prospective listeners to type the address of a graphic into the search bar. If you are using Instagram, put the link in your bio, and let people know in your post that, "link is in my bio."
Let your digital books market your audiobook as well. Whether it is the same version of the book in digital form or a different book, use the page before your book begins, or the first page after the book ends, to promote your audiobooks. You can put the link on the page and make it clickable. That way, when someone is beginning or finishing your book, and they are interested, they can go right from the digital edition to the audio.
Make sure to shortcut your links using websites like bitly.com to keep from posting extremely long links. With Audible, you can customize your link, and if someone signs up from that link, you get a $50 bonus. So, you get a personalized link, cash, and a new listener.
Also, include links to your audiobook on your author pages under the about section, and on your websites. Research has shown that it can take a person seeing something up to eight times before they purchase it, so make that link available wherever you can.