Black hat to sell Amazon Kindles, any advice?

Hello everyone, need some advice

does anyone know if there's some advice on how to get some black hat gains on Amazon Kindle? I have 6 cookbooks in Kindle and paperback (soon on Audible too) but so far I made almost no money out of them, Amazon has cracked down in the last year on black hat practices like review swaps

I had a read at the link below but there doesn't seem to be anything about it

https://www.blackhatworld.com/seo/read-this-before-you-ask-an-seo-question.1040158/


Any advice or guides that can explain how to do it?

Many thanks

Build your own store/review blog where you can do SEO to get traffic then link them to amazon for ur books you make reviews on.