Congrats on finishing it! I also did a comic book and posted on Amazon, a cool thing you can do is use their print on demand system, it's awesome to have a physical token of your achievements.
You could develop a following around the books themes and subjects. Let's say you're making a post apocalyptic book, talk about how Fallout fans could be interested in it, and other similar IPs. Also small written parts that would do good in verticals would be great such as an out of pocket...