By comparison, Amazon's affiliate commission rate is under 5% for books (a whopping 10 times less, which means you'd have to make over ten sales of a $4.99 book just to earn $2.50).
Or you could just sell one of my books.
(And earn over $20 for 10 sales)
1) First, you'll need to create a Gumroad account so that you can get paid, since the affiliate program is run via Gumroad.
With Gumroad, while they possibly are a little less known, they are up there with Patreon and Paypal in terms of security and reliability.
2) After that, fill out the form at the bottom of this page, so that I can add you into the affiliate program (this is a manual process on my end).
This is what I have to fill out.
3) Once approved and added, Gumroad will send you an email with a unique link that will attribute any sales within 30 days to you.
Just remember to use your affiliate link provided by Gumroad when you try to make a sale (and Gumroad should give you specific links for specific products, in case you want to send someone directly to Book 1 of a series).
My books are offered in epub, mobi, and PDF format, so that anyone buying can read it on any device.
Some ideas of where you can share include appropriate Facebook groups, forums, discord, online communities, and anywhere else where you know people who might be interested in my stories. (You could also always try advertising, but that's up to you if it's worth it.)
Be care not to spam though.
It's best to share your affiliate link where it's actually allowed and desired (and keep in mind that my books are written for 18+ readers).
If you have any questions, you can also use the form below to ask, but the best way to contact me is via Patreon (if you're a supporter).
If you have a question not related to the affiliate program, then please visit my Contact Page.
After submission, please give me at least a week to respond.